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High School Reunion with 1967 Sedan DeVille

Started by savemy67, December 07, 2014, 11:57:13 PM

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savemy67

Hello Nicolas,

The spring is a bi-metal spring - a sandwich of two different metals that expand and contract at different rates.  I will try to apply some heat to my heat riser spring tomorrow to see if it works.  It isn't pretty, but I have no use for it.  If it works, you can have it for postage (Do I recall correctly that you live overseas?)

Christopher Winter
Christopher Winter
1967 Sedan DeVille hardtop

savemy67

Hello All,

As many of you know, working on an old car that has not yet been rebuilt or restored involves working with greasy, grimy, and dirty parts.  One of the consequences of rebuilding sub-assemblies (like the starter) is the fact that sooner or later, the sparkling clean, rebuilt sub-assembly has to be put back on what still might be a greasy, grimy, dirty car.  Sometimes a clean, rebuilt component has to be maneuvered through a maze of hoses, wires, and tubes which in and of themselves are not a high priority on the clean-up list, but which can brush against a clean component and sully your best efforts at installing a clean part.

Photos 4024 and 4025 show the right side of my engine block looking toward the front of the car and toward the rear of the car respectively.  In photo 4025 you can get a good idea of the amount of accumulated grime after 48 years and 90,000 miles.  I did not want to install my rebuilt starter (or any other rebuilt component) with that mess in such close proximity.

It is one of life's ironies that elbow "grease" is what is needed to remove the "grease"  from the engine.  I cleaned the sides of the block and the oil pan while lying on my back under the car (remind me not to do another car project until I have a garage and a lift).  I used a flexible putty knife, wire brushes, picks, soft brushes, scrubby pads, and thinner.  I was able to remove the transmission lower cover and clean it at a bench (photo 4049).  The cover was then glass beaded and painted.

Photos 4060 and 4144 show roughly the same views as photos 4024 and 4025, but after a little house cleaning.  The improved operational field will make installation of the rebuilt components a little less irksome.  My rule of thumb is that if I touch it, I clean it.  Photos 4046 and 4053 show the starter front support bracket and the left-side engine block to transmission lower cover strut before and after cleaning.  These parts were painted black.  I also clean virtually all nuts and bolts if they are removed and reinstalled.  The engine to transmission strut is an inconsequential part, but each and every part that is refreshed or rebuilt is one less part with which I have to be concerned.

I recall that elsewhere on this forum, a discussion ensued about whether there was a gasket for the transmission lower cover (my car is a '67 with a 429 and a TH400).  Photo 4052 shows the gasket or seal that was installed on the crankshaft cut-out of the transmission lower cover.  Since the transmission lower cover is not sealed to the weather, I can only guess that maybe this gasket/seal was a vibration damper so no annoying rattle would emanate from the transmission lower cover's close position to the oil pan.

One drawback to cleaning the block and pan is that both parts are made from ferrous metal.  Here in Maryland, the week before Christmas was so humid - some days reached 90 percent relative humidity - that surface rust formed on my block and pan.  I crawled back under the car with a scrubby and some acetone and trans fluid and wiped all surfaces to remove the surface rust, and to leave a film of transmission fluid to protect the metal against future surface rust.  Eventually, the engine may get pulled, at which time it will get painted, but until then I am OK with my present efforts.  And I should not have to do as much laundry now that the engine and its parts are becoming less grimy.

Christopher Winter
Christopher Winter
1967 Sedan DeVille hardtop

savemy67

Right or Left?

Hello All,

No, I am not referring to Donald Trump or Bernie Sanders, but to my power steering gearbox.  My gearbox is a Saginaw recirculating ball with power assist model 800.  The casting number on the gearbox is 5687962.  As far as I can tell it is the original gearbox.  While my steering is functional, I noticed two issues with it given the few miles I have driven the car.  The gearbox leaks a little - just enough to wet the exhaust pipe and smoke for a minute or two when the pipe gets hot - and there is a little play in the steering that does not seem related to the tires or suspension.  These two issues, plus removing the gearbox for better access to my left exhaust manifold, hastened the need to rebuild my gearbox.

Servicing the power steering gearbox seems to require a host of special tools.  I have tools like a Pitman arm puller and bearing and seal drivers, but I had to buy a low-scale (0 - 60) beam type, inch-pound torque wrench.  I will have to fabricate a rack piston ball nut arbor, and for seal protectors I can use tape.  Photos 4139 and 4140 show the spanner tool I made using 1/4 inch rod stock, my bench grinder, and my vise.  The spanner tool is used to remove, install, and adjust the adjuster plug in the upper end (the steering column end) of the gearbox.  The adjustment sets the thrust bearing pre-load.

Dis-assembly revealed that the inside of the gearbox was very dirty.  Photo 4141 shows some of the gunk from inside the gearbox, on the end of a screwdriver.  Given the gunk that was in the gearbox, I was not too surprised to find some wear in both the rack piston bore and the rotary valve bore.  Hopefully the wear is not so great that new seals and rings won't work - we'll see.

Photos 4157, 4158, 4159, and 4161 show the gearbox's major sub-assemblies cleaned, re-assembled, and ready to go back in the gearbox.  Respectively the photos show the rotary valve assembly with stub shaft, the sector shaft, the internal side of the adjuster plug assembly, and the rack piston with worm shaft installed.  Two of the sub-assemblies require a good deal of patience and care when re-assembling them.  So much so that many people do not attempt to rebuild their power steering gearbox.  The rotary valve assembly (photo 4157) is a high-precision sub-assembly.  The Cadillac shop manual makes it abundantly clear that if the slightest defect is found in any part of this sub-assembly, the entire rotary valve assembly should be replaced.  Well that was easy for a Cadillac dealer to do in the late 60s or early '70s, but it is not at all easy to do 48 years later.  Nevertheless, because most of the o-rings in my gearbox were decrepit, and there is an o-ring within the rotary valve, I dis-assembled my rotary valve assembly so I could replace the o-ring on the spool valve.  If you are considering doing this to your gearbox, be very careful.  I deviated slightly from the shop manual rotary valve re-assembly procedure based on the video found here:

http://datab.us/UJ-89YhvAXU#Saginaw 800 Power Steering Gear Box Part 1

Note that this video uses the same Saginaw model number power steering gearbox, but from a later model GM car, so there are a couple of small differences compared to my '67's gearbox.  Watch all 5 parts if you are considering rebuilding your power steering gearbox.

The other persnickety sub-assembly is the rack piston (photo 4161)  This is the component with the ball bearings that recirculate around the wormshaft.  The hard part is loading the ball bearings into the rack piston and getting them to stay there when you re-assemble the gearbox.  I used the wormshaft to load the ball bearings in the rack piston, and then inserted a home made arbor while removing the wormshaft.  The wormshaft is assembled to the end of the rotary valve for installation into the gearbox housing, so you need an arbor in the rack piston to keep the ball bearings in place when the wormshaft is removed.  Petroleum jelly is also very useful in keeping the ball bearings in place.  Given all the pieces and parts one has to hold together during assembly, I think an octopus would make a great mechanic.  More detail will follow in my next post.

Christopher Winter

Christopher Winter
1967 Sedan DeVille hardtop

savemy67

Straight Ahead

Hello All,

Photo 4151 shows the 24 ball bearings from my gearbox.  To my eyes (and my two neighbor's eyes), 11 of the balls are dull/dark and 11 are shiny/light.  It was difficult to determine the coloration of the two balls in the lower right of the photo.  The difference is important as the different shading represents two different sizes of ball bearings, and the ball bearings are supposed to be installed into the rack piston alternating light and dark.  The shop manual stresses the importance of no two same colored ball bearings being installed next to each other.  The shop manual also gives the dimensions of the ball bearings which, in 1967, could be obtained from GM in four different groups varying  on average by no more than two and a half ten thousandths of an inch.  Talk about splitting hairs - on a two ton car!  But then again, Cadillac's reputation was established by just such precision.  I succeeded in getting the ball bearings installed into the rack piston on my third attempt.

As always for me, cleanliness is next to Henry Lelandliness.  Photo 4147 shows the stub shaft which I wanted to clean like all the other parts in the gearbox.  If you look closely at photo 4147 you will see what appears to be a pin at each end of the stub shaft.  In fact, the stub shaft is comprised of six pieces - the splined shaft, a torsion bar inside the shaft (photo 4162a from the web), two anchoring pins (the ends of which are visible in the photo), a locating pin, and an o-ring.  The locating pin locates the stub shaft in relation to the rotary valve into which the stub shaft is assembled (see previous post photo 4157).  The shop manual states that if there is any evidence that the o-ring inside the stub shaft is leaking, the entire stub shaft rotary valve assembly should be replaced.  I had some concern about this because when I cleaned my stub shaft with thinner, and blew it dry with compressed air, some fluid appeared to come out of the shaft.

The shaft looks like it could be disassembled, so I did a little research to see what I could find out about the stub shaft.  I discovered that the stub shaft can be serviced.  Some off-road and racing groups modify the steering feel of the Saginaw power steering gearbox by replacing the torsion bar in the stub shaft with a thicker, stiffer torsion bar.  The only problem for me is the process requires some special (and expensive) equipment that is generally not available for the home garage.  I did locate and contact a former Saginaw engineer who advised me to leave the stub shaft as is because of the specialized equipment needed to service it.  The engineer’s name is Jim Shea, and he was responsible for the rag joint and power steering hose assemblies for all GM cars in the early ‘70s.  He has some interesting papers on steering components here:

http://jimshea.corvettefaq.com/?cat=4

I will just have to wait and see if there is any problem with my stub shaft to torsion bar o-ring.  Regardless, I proceeded with the rest of the gear box re-assembly.

Photo 4164 shows the gearbox cleaned, painted, and assembled in a holding fixture.  I made two modifications to my ‘67 gearbox based on design changes made by GM on later gearboxes.  The two fillister head screws that hold the ball guide to the rack piston require a torque of 12 foot pounds per the manual..  I replaced the slotted fillister screws with hex cap screws because it is easier to get a socket to stay on hex cap screws while trying to torque the screws than it is using a slotted screwdriver bit (photo 4175).  I also discovered that the shop manual is incorrect regarding these screws.  Page 9-50 of the '67 Cadillac shop manual shows a chart with fastener sizes and torque specifications.  The chart lists the screw size and torque for the rack piston ball guide clamp screws as 1/4 - 20, and 12 foot-pounds.  When I installed the original fillister head screws with the screwdriver bit, and when I replaced the fillister screws with the hex screws, trying to get 12 foot-pounds on the screws just did not feel correct.  The screws behaved as if the torque was too much.  If I had tried to torque the screws to 12 foot-pounds as specified, the threads on the screws would have pulled.  The correct fasteners are 1/4 - 28, and according to several engineering and bolt sites I researched, the torque for the factory screws should be about 6 foot-pounds - half of what the manual calls for!  The hex head screws I ultimately used are grade 5, and I torqued them to 6 foot-pounds and used thread-locker on them.

The other change was the rack piston end plug (not the housing end plug).  This plug (photo 4174) is originally a 1/2 inch square drive cast aluminum plug.  When I was trying to torque the plug to 75 foot pounds per the manual, the square drive adapter slipped out and damaged the plug (photo 4174, left), so I replaced it with a hex head plug which is easier to torque (photo 4174, right).

I used the shop manual procedures to set the bearing pre-load and to make the sector shaft adjustment.  With new rings and seals I was able to get all the adjustments within the specifications called for in the shop manual.  In making the adjustments, a 3/4 inch deep socket fits perfectly over the splines of the stub shaft.  I noticed that when I turn the socket, the sector shaft immediately turns.  This is the case in either direction and is a good indication that there is no play in the gearbox.

Photo 4153 shows the cleaned power steering cooler.  I ordered new hoses, and will clean and re-use the original tower clamps on the return hoses.  Since both the rebuilt power steering pump and gearbox are empty of fluid, I expect it will take some time to rid the system of air. 

Christopher Winter

Christopher Winter
1967 Sedan DeVille hardtop

Scot Minesinger

Chris,

Yes once worked on a 67 DeVille and the flywheel cover was the dirtiest part on the engine.  However because it was grease on aluminum, it sure cleaned up nice.  The tubular brace you had off the car before and after clean up had some small portions of the Cadillac blue paint on the one I did so I repainted them.  What is your eta for roadworthiness?
Fairfax Station, VA  22039 (Washington DC Sub)
1970 Cadillac DeVille Convertible
1970 Cadillac Sedan DeVille
1970 four door Convertible w/Cadillac Warranty

savemy67

Hello Scot,

In the past 90 days I have rebuilt the alternator. starter, power steering pump, and power steering gearbox.  I have also removed and replaced both exhaust manifolds.  Until I finish connecting the exhaust pipe through the muffler, I won't start the car, which I need to do in order to check that all the rebuilt components are functioning properly.

After I establish that all those systems are good to go, I will seriously consider rebuilding my transmission.  After that, I expect that the car can be driven without much concern.  However, I will probably remove the carb and intake manifold, and the lifter valley cover.  I will inspect and rebuild the lifters if needed.  I will clean and paint the lifter valley cover and intake manifold.  I will probably also remove, clean, and re-install the pushrods, valve rocker arms and pedestals.

Optimistically, I think an ETA for road-worthiness is this summer.  The car is not garaged so working on it outside is subject to the weather.  Show-worthiness is on a completely different schedule.  I have thought about entering shows with the body/paint as is, and placing a large "BEFORE" sign in the windshield.


Christopher Winter
Christopher Winter
1967 Sedan DeVille hardtop

DeVille68

nice work.

My car is currently also not running. Have removed the carburetor and fuel line and filter. No battery either...
1968 Cadillac DeVille Convertible (silver pine green)

Evan Wojtkiewicz

Hey Chris,

I got a chance to go over your whole thread, and I have to tell you that you're doing an amazing job. Both with the repairs and the write-ups. I'll admit that I'm not the most mechanically able guy (yet) and I'll also have to admit I was a bit intimidated my the depth and completeness of your posts, but It's great to have the info. My car has similar issues with the exhaust and valve noise, so I'll be re-visiting your writings in the spring when it's out of storage.
CLC 29623

1967 DeVille convertible

savemy67

Hello all,

It has been about 60 days since my last post.  With my car outside, I am not able to work on it as much as I would like during the Winter months.  However, since my last post, the components that I rebuilt over the previous 90 day period (alternator, starter, power steering gear and pump, exhaust manifolds) all seem to be functioning properly.  When I started my car around the first of February, I grounded the coil so the car would not start until I saw oil pressure.  A few drops of gas down the carburetor vent and it started and idled well.

Today, after six weeks of dormancy, I started the car again because I needed to move it so I can rebuild my transmission.  Likewise, I grounded the coil, saw oil pressure, and dribbled some gas down the carb vent, and again the car started immediately and idled well.  Before I started the car (around the first of February and today), I checked the battery with my DVOM and observed 11.99 volts at about 47 degrees Fahrenheit.  The clock in the car appears to be the only current draw, and apparently it is not drawing much current.

So even as the weather warms, I am putting my car out of commission again so I can rebuild the transmission.  During the little time that I have driven my car, the transmission seems to have shifted OK.  The only problem I  noticed is that when the transmission is warm, the car will buck and stall when the transmission has downshifted to first and the car approaches a stop.  This problem may or may not be transmission related.  My switch pitch/kickdown switch is broken and not connected.  I need to get it fixed by the time I finish the transmission.  In any event, the TH400 is 49 years old, and I know that the car sat for a few years during its life, so a rebuild can't hurt.

I once saw a TH400 dismantled in under 11 minutes (out of the car), but I have no desire to set any rebuilding records, so I will take my time.  I am also limited on space.  I live in a little row house in Baltimore County that was built in 1939.  The style of the house incorporates a 1-car garage built into the lower level at the rear of the house.  Photo 4214 shows my garage full of tools, supplies, and lots of stuff - so much stuff that I had to build a little shed recently (photo 4215), so I could make room in the garage to work on the transmission once it is out of the car.

Photo 4212 shows the driveway where I will park the car when I pull the transmission.  My driveway is not level.  It slopes from the garage to the street and it slopes from right to left.  This always makes for a challenge whenever I jack up my car.  I have jack stands rated at 6 tons, but I won't use them for the transmission project because I feel they will have to be set so high that the car might not be stable on the sloped driveway while I wrestle the transmission out of the car.

Without a lift, the car has to be raised high enough to lower the transmission and pull it out from under the car, clearing the exhaust, frame, and whatever else might get in the way.  I had enough scrap wood to make a set of ramps (photo 4217) and some crib blocks (photo 3923).  I drove the car onto the ramps which raised the rear of the car about 9 inches.  I jacked up the front of the car and put three crib blocks under each front tire.  This raised the front of the car about 19 1/2 inches off the driveway (photo 4222).  The set-up may look a little rickety, but as I always shove my car side to side and back and forth to test stability, this set-up is solid

My floor jack's lifting range is not sufficient to raise the front of the car as high as I did with the jack resting on the driveway.  I thought about getting a saddle extension for the jack, but after trying something similar with wood blocks, and finding the wood block extension insufficiently stable, I made a large jack base on which I can place the jack and securely gain about 8 inches of height (photo 4220).

I am not sure that I have enough clearance based on the fact that the transmission removal adapter for my floor jack adds a few inches of height.  I may need to modify the adapter based on a few preliminary measurements.  I know I have enough room to separate and lower the transmission from the engine, but I am not yet positive that I have enough height to clear the frame side rails.  I may make a trestle to support the rear of the engine and pull the transmission forward under the trestle.  I will cross this bridge when I get to it and post photos.
Getting the car elevated was the first day's chore.  The next day's chore will be to drain the fluid from the transmission, and disconnect all the parts attached to it (driveshaft, shift linkage, cooler lines, speedo cable, etc.), and figure out if I need to modify the transmission removal adapter, build a trestle to support the rear of the engine, and or raise the front of the car a few more inches.

Christopher Winter
Christopher Winter
1967 Sedan DeVille hardtop

savemy67

Hello all,

The goal for the second day of my TH400 rebuild was to get the transmission out of the car with both it and myself intact.  Since I am posting this message, you can assume that I still have all ten digits on my hands.

The transmission removal procedure in the shop manual makes the process sound like a piece of cake.  I ran into trouble with two of the steps outlined in the shop manual.  The transmission lower cover, the part that covers the lower half of the ring gear and torque converter, could not be removed on my car without loosening the exhaust Y pipe nuts at the exhaust manifolds.  The shop manual does not mention that the Y pipe needs to be loosened.  It is possible that I have an aftermarket Y pipe that is not bent the same as the factory Y pipe.  In any event, keep this in mind if you have a '67 rear wheel drive model.

The other trouble I had was with disconnecting the cooler lines.  To provide better access, I removed the modulator.  I have a set of line wrenches which I used, but even with the line wrenches and enough room to swing them, the fitting attached to one of the lines twisted the line.  I cut the cooler lines using a tubing cutter (photo 4232) and will plumb a new connection when the transmission is replaced.

In my previous post, I had a concern as to whether or not the front of the car was high enough off the ground to be able to get the transmission out from under the front of the car while the transmission was still on the jack and jack adapter (photo 4229).  Pulling the transmission from under the front of the car required me to construct a support for  the rear of the engine that would allow the transmission, on the jack, to pass through.  I originally envisioned some sort of trestle, supported at the sides, and holding up a block under the oil pan.

I had to discard this idea because there are too many steering and exhaust components in the way.  Having recently read an engineering textbook, I decided to make a truss to support the rear of the engine.  A truss is a series of triangles joined together.  I don't have space for a series of triangles, so my truss consists of just one triangle (photo 4236).  I made a u-shaped cradle out of 2 x 4 lumber that contacts the oil pan rail and not the pan bottom (photo 4233).  The truss supports the cradle (photo 4234).  The bottom ends of the truss are wedged into the crib blocks that are holding the weight of the front of the car, so they are virtually immovable (photo 4235).  The weight of the back of the engine - maybe 200 pounds - bears down on the cradle.  This force would ordinarily want to force the top of the truss in or out, but since the top of the truss is locked in place by the weight of the engine bearing down, and the stationary positioning of the bottom of the sides at the crib blocks prevents the sides from moving out, nothing can move given the load.  Not only did the truss provide sufficient support for the back of the engine, more importantly, the truss allowed me to pull the transmission from under the front of the car, through the truss.  I did have to remove the torque converter, and tilt the transmission forward.

The transmission removal took me all day.  I must have crawled under the car and back out again 30 to 40 times.  Leverage suffers when you are lying on your back, so procedures that can be done quickly when standing on your feet, take more time when lying on your back.

At least the hard part is done (until I have to install the transmission) so now the fun part starts - disassembling, inspecting, cleaning, assembling.  The fluid was reddish-brown, and there is a faint burnt odor, so I think my friction components are due for a change.  Hopefully there will be no surprises when it comes to the hard parts.

I have the shop manual, as well as Cliff Ruggles' TH400 book, ATSG's TH400 book, and a Chilton manual covering 1967 cars.  I just bought the Ron Sessions TH400 book, used, on Amazon for $12.  This book is usually hard to find at a reasonable price, but there were a few of them on Amazon as of Wednesday night, March 23rd.  There are also TH400 manuals on the CLC Modified Chapter website, so there are plenty of references available.  Next up,  disassembly of the transmission.

Christopher Winter
Christopher Winter
1967 Sedan DeVille hardtop

DeVille68

Hi Christopher,

Nice work!  8)

You have built yourself some great ramps. What an idea. I have to keep this in my mind.
Best regards,
Nicolas
1968 Cadillac DeVille Convertible (silver pine green)

savemy67

Hello all,

The goal for the third day of my TH400 rebuild was to get the transmission disassembled as far as the removal of all the components from the case was concerned.  By the end of the day, I wanted a bare case.

My first chore was getting the transmission on my workbench.  Since the transmission was on the floor jack and transmission adapter, I raised the whole works to its full height.  This put the transmission just a few inches below the workbench surface.  I was able to wrestle the tailshaft onto the workbench, and then lift the front of the transmission onto the workbench.  Despite being drained of fluid and having the torque converter removed, the transmission weighs a little more than this 60 year-old cares to heave in one go from the floor.

Even though the transmission was drained, enough fluid remained in the case to cause a mess upon disassembly.  I put an old towel on my workbench and put the transmission on the towel.  I also had a bunch of old rags available.  Before long, I had all the internal components separated from the case.  Photo 4259 shows the rotating parts.  While disassembling the transmission, I examined the parts as they came out of the case.  I have a first-half-of-the-model-year '67, so the filter in my transmission is the rectangular box type with the "flying saucer" pick-up, not the "broiler pan" type of filter that flops around..  Photo 4240 shows the pick-up for the filter.  Photo 4239 shows the inside of the pan, and you can see where the filter pick-up contacts the pan.  Also notice that the pan has a depression in this area - commonly referred to as a "heel print".  The heel print is the lowest part of the pan so it makes design sense that the pick-up is located at the heel print.  I am curious if anyone knows why GM switched to the "flop around" filter in mid-model year.

You can see that the pan and the fluid  in it are not full of sludge.  The transmission was fairly clean, with no observable metal shavings, or friction bits floating in the fluid, but the fluid is brown.  Photo 4266 shows a sample of the old fluid and a sample of new fluid on a white piece of paper.  Given the color of the old fluid, I think it was time for a rebuild.  The fluid did have a slight "cooked" aroma, not burnt, but not minty fresh.  The bands and drums show evidence of heat, but nothing too severe - just what I would have expected on a 49 year old, 90,000 mile transmission.

Before the rotating components are removed from the case, the input and output shafts' endplay needs to be checked.  Photos 4250 and 4252 show my dial indicator set-up to measure the input shaft endplay, which measured .019", which is within spec.  A dial indicator is one of the few special tools one should have when rebuilding any transmission.  Mine is 40 years old and American made.  The TH400 does not require many special tools.  Other than a dial indicator, the only other special tool I would recommend purchasing is a good bushing driver set.  Just about every other tool one might need can be fabricated from threaded rod, nuts, washers and bolts, C-clamps, guitar strings, old pipe fittings, etc.  Photo 4277 shows a slide hammer I made to remove the pump from the front of the case.  Some people beat on the stator shaft with a rubber mallet, or they pry the pump out with a big screwdriver levered against the inside of the case, but I wanted to be more subtle.  Photos 4248 and 4249 show how I used a 3/4 inch socket to depress the kick-down/switch-pitch connector tabs to aid in removing the connector from the side of the case.

At the end of the day, I had a bare case.  My plans for the next episode of my transmission rebuild call for cleaning the case and extension housing, and prepping the parts for paint.

Christopher Winter
Christopher Winter
1967 Sedan DeVille hardtop

savemy67

Hello all,

The goal for the fourth day of my TH400 rebuild was to get the transmission case and extension housing prepped for paint and primed.  Even though the transmission case is aluminum, it still required a lot of cleaning after almost 50 years.

Photo 4265 shows the extension housing (behind cross member) before being subjected to a scrubbing with paint thinner.  This chore is very messy, but necessary for a good rebuild.  As I have been known to say, cleanliness is next to Henry Lelandliness.  I use a mortar pan which has plenty of volume for parts and solution, and helps contain the solution and sludge.

Photo 4267 shows the extension housing after the thinner bath.  It is much improved, but not yet ready for paint.  Photo 4278 shows the case after its thinner bath.  You can see that the aluminum is still dirty/stained.  Also notice that I plugged the holes in the case (on this side of the case, from left to right, the speedometer opening, the kick-down/switch-pitch connector opening, and the shift yoke opening) in preparation for sandblasting the case.  I plugged the holes in the other side of the case, and found a bucket lid that fit the pump opening in the front of the case.  I also installed the pan and governor cover, and masked off the tail housing end.  All the plugs were placed to minimize entry of the abrasive when the case was sandblasted.

Photos 4279 and 4280 show my home-made blast cabinet and the transmission case inside (the photo with the case inside was taken after I sandblasted it, hence the pump opening is not covered).  Having a blast cabinet has been extremely useful.  I had most of the material for its construction at hand.  I had to buy one 4 x 8 sheet of OSB, gloves, toilet flanges (to mount the gloves), and a siphon feed sandblast gun (cost of parts under $100).  Photo 4283 shows the improvement I made to the end of the pick-up tube of the siphon feed gun.  The end of the tube was not perforated as seen in the photo.  I "Swiss Cheesed" the tube and the difference was night and day in the ability of the gun to draw abrasive.  Photo 4282 shows the tube inserted through the side-bottom of a 5 gallon bucket.  The bucket holds about 50 pounds of abrasive.  I have both glass beads and coal slag.  I used coal slag on the transmission case.

Photo 4281 shows the case after sandblasting.  I rinsed it with acetone, and used brake cleaner to flush the internal passages.  The brake cleaner revealed that there was still a fair amount of oily residue on the case, so into the "parts washer" it went (photo 4284).  After a soak in the parts washer, with hot water, Spic n Span, and Dawn dish detergent, I rinsed the case with a hose and nozzle and blew it dry with compressed air.  Well, it smells great, but there is still enough of an oily residue on the case that I will have to repeat the parts washer process, or buy some more brake cleaner, or contact my local transmission rebuilder to see if they have an aluminum-safe hot tank.  Then the case should be ready for paint.

My TH400's case seems much more rough and porous than the aluminum Powerglides I have rebuilt.  The surface of the case feels like cast iron, even inside the bell housing area.  Perhaps this is why the case is still holding a residue after all my efforts.  Well, I want the paint to stick, so it has to be clean.

For my next installment (day 5), I hope to have the case primed, and begin the disassembly and inspection of the internal rotating components.

Christopher Winter
Christopher Winter
1967 Sedan DeVille hardtop

savemy67

Hello all,

I had a few hours available for the fifth day of my transmission rebuild, and I was able to take a good look at the condition of the friction material, steels, bushings, washers, planetaries, and pump and gears.

Photo 4296 shows one of the bands from the transmission.  As can be seen, the color of the band is very dark brown, possibly indicating some heat damage.  Also in the photo, although a little difficult to see, are some pock marks where the friction material has come off the band.  Photo 4303 shows one of the friction clutches, and it is evident that some friction material has worn off the clutch.  This particular disc is one of the worst.  Photo 4297 shows some other friction clutches that do not have as much wear - the manufacturing stamps are still visible.  Overall however, it is time to replace all the friction material in the transmission.

Photo 4300 is representative of the clutch pack steels and drum that are subject to friction.  There is a slight discoloration to the steel surface, but no blueing of the steel.  The discoloration will probably clean up with some sandpaper.  Like the clutch pack steels, the other hard parts in the transmission - shaft splines, drums, drum hubs, roller/sprag clutches, and gears - all seem to be in good, reusable condition.

Photo 4305 shows the lip seals from one of the drum assemblies.  While pliable enough to be turned into pretzels, the seals are not pliable enough to return to their original shape.  The drum pistons that are sealed by these seals were easily removed with the seals in place.  A properly fitting and functioning seal should provide a little resistance to the removal of a drum piston.

Photo 4316 shows a bushing in need of replacement.  Several bushings showed scuffing and wear, so I will get replacement bushings.  Many transmission rebuild kits do not come with bushings, so scrutinize the contents of any kit that you purchase.  You may have to buy the bushings separately.  Like the bushings, many kits do not come with thrust washers.  A few of the washers in my transmission show wear similar to that of the bushings, so the washers will get replaced.

One operation that needs to be done when disassembling any transmission, including my TH400, is the compression of the clutch pack springs, so that the clutch pack drum piston can be disassembled.  Photo 4308 shows a piston being held by the green springs which are held by a retainer which is held by a snap ring (with its opening toward the camera).  Photo 4310 shows the assembly in my press with a scrap of PVC pipe.  The cutaway is for access to the snap ring with snap ring pliers.  When the snap ring is removed, the press is released, and the retainer, springs and drum piston can be removed from the clutch pack drum.  A gentle touch is needed on the press as the springs do not compress much.

There will be many things that need to be measured before, during, and after the assembly of the sub-components and entire transmission.  I plan to record all the clearances and specifications.  One measurement is seen in photo 4317.  I used a hand-held vacuum pump to draw 16 inches of Hg on my vacuum modulator.  The vacuum held for 4 minutes before I released it.  The modulator is the original style, with the adjustment for altitude.  I don’t know if it is the original modulator.

I will need a rebuild kit with everything except the clutch pack steels.  The steels do add to the cost of many rebuild kits, so it will be more economical if I don’t have to buy them.  However, getting some of the other parts like bushings and washers from the same kit vendor may not be possible without getting the steels as well.  To minimize shipping charges, I would like to get everything from one vendor  I should be able to get all the parts I need for about $200.

Christopher Winter
Christopher Winter
1967 Sedan DeVille hardtop

savemy67

Hello all,

I was able to procure a rebuild kit for my TH400 transmission that did not include the clutch steels.  This saved a few dollars that I applied to purchasing replacement Torrington bearings, thrust washers, and a bushing kit.  I purchased the kit and other parts from Fatsco Transmission Parts in New Jersey.  With shipping, the cost was about $223.

My transmission is the variable pitch version of the TH400 found on '65 through '67 Cadillacs, Buicks, and Oldsmobiles.  As such, there are some differences between my '67's TH400, and '68 and later TH400s.  Photo 4321 shows the two bushings that are found in the stator support shaft (part of the transmission oil pump front cover).  The bushing on the left - a new bushing - is .500" long.  The bushing on the right - one I removed from the stator support shaft - is .400" long.  The shorter bushing is needed because it has to clear the two oil holes in the pump cover used for the variable pitch stator - as seen in photo 4329.  My rebuild kit did not have this shorter length busing, nor could I find any kit that did.  The kit contained two of the .500" length bushings, one of which I modified by grinding it down to .400" long.  Photos 4330, 4333, and 4334 show the process of marking the bushing with tape used as a guide, grinding the bushing using my drill bit sharpening grinding wheel, and comparing the newly ground .400" long bushing with the .500" long bushing after a little scraping and filing of the edges of the ground bushing.  Photo 4335 shows the bushing installed.

When a bushing is installed, there is a slight crushing of the bushing - bushings of this type are an interference fit in the bores.  After bushings have been installed, it is important to check the fit on the shaft that will be supported by the bushing.  In this case, the two stator support shaft bushings support the transmission input shaft.  Photo 4336 shows the forward drum and the input shaft.  The two shiny areas on the shaft are where the shaft is supported by the bushings.  Photo 4339 shows the transmission oil pump front cover with the stator support shaft, assembled over the forward drum and input shaft.  I was able to rotate the pump cover easily with no apparent looseness.  Bushing clearance should be in the .002" - .008" range.  Mine felt like "buttah"!

Christopher Winter
Christopher Winter
1967 Sedan DeVille hardtop

DeVille68

Thanks for the update! I am sure your detailed pictures will be of value to someone in the future.
1968 Cadillac DeVille Convertible (silver pine green)

savemy67

Hello all,

Due to work, I have only had a little time to work on my transmission.  However, I have rebuilt most of the sub-assemblies, and I started reassembling the transmission today.

While I do not find rebuilding transmissions very difficult, I do find that paying attention to little details is important.

Photo 4319 shows the spool valves and bushings from the valve body.  It is important to keep these in order, so I used a piece of fluted molding to keep the valves and bushings from rolling off my workbench.  All metal parts were cleaned in thinner, and then rinsed with acetone and blow dried with compressed air.  Parts were reassembled using transmission fluid and or petroleum jelly.  Petroleum jelly will dissolve and mix with transmission fluid at operating temperature.  Petroleum jelly also has the benefit of holding parts in place.

I replaced all the bushings in my transmission.  Photo 4343 shows the two original extension housing bushings adjacent to the new extension housing bushings.  The new bushings are longer than the original bushings, and my rebuild kit came with only one new bushing.  Considering the operating conditions of the driveshaft yoke in the extension housing, I wanted to have two bushings in the extension housing - like Cadillac originally installed - in order to support the yoke fore and aft.  Photo  4345 shows the two new bushings on the driveshaft yoke.  I cleaned the yoke and the bushings slid on with no noticeable play.  When the bushings were installed in the extension housing, the yoke would only slip past one of the bushings.  I needed to hone one of the bushings in order to get the yoke to slip through both bushings.  Most bushings get "crushed" when installed in their bores, so either my extension housing was a little out of spec, or one of the bushings was a little too thick.  I suspect the later because I encountered the same condition with the sun gear shaft bushings - only one of the sun gear shaft bushings fit over the mainshaft, and I had to hone a bushing.  The important point is to check that everything fits properly, and that clearances are within specification.

Given that there were some recent posts on this forum regarding driveline vibration, I think having two extension housing bushings really helps align the splined end of the transmission output shaft and the driveshaft yoke, eliminating as much as possible any excessive run-out.

Photo 4354 shows that my dipstick protrudes about 1.5" below the pan rail.  I took several measurements of the dipstick.  Photo 4355 shows the original 0-ring that seals the dipstick tube, and the new dipstick tube boot that came in the rebuild kit.  The boot seems like a good idea, but it appears to be too thick to use with my dipstick tube in my transmission case.  I will probably double-up on the o-ring.  Photo 4358 shows the distance between the end of the dipstick and the full mark on the dipstick.  This information allows me to know where the full mark is in relation to the pan rail should I change the relationship of the tube and the case.

Photo 4360 shows the reassembled gear train which consists of, from left to right, the output shaft, the output carrier (containing a planetary gearset), the reaction carrier (containing a planetary gearset), the center support (with sealing rings), and the splined ends of the sun gear shaft and mainshaft.  The washer and locking pliers are used to hold the assembly in a vertical position when installing the 40 pound assembly in the case.  The gear train assembly makes contact with a selective thickness thrust washer that rests against the case.  Photo 4367 shows the thrust washer that is original to my transmission.  Two of the three tabs are notched (this may not be to visible in the photo) - at the 10 and 6 o'clock positions.  Per the shop manual, this indicates that the washer is .094" - .098" thick.  I measured my washer with a micrometer at .095" thick.

Before dis-assembling the gear train from the case (at initial tear-down), I measured the end-play of the output shaft and obtained a reading of .000".  There should be .003" - .019" of end play.  My rebuild kit supplier listed a thinner selective thrust washer, but it is not available from the supplier.  I installed the rebuilt gear train in the case this afternoon and checked the end play.  Unfortunately, the end play is still .000", which is not enough, so I will need to find a thinner selective.  The factory offered a washer (with no tab notches) measuring .078" - .082".  This will work for me.  I just have to find one.  I have removed the gear train from the case, and hope to find a usable washer soon.

Once the washer arrives, and hopefully restores the end play to specification, the rest of the reassembly should progress rapidly.  The direct and forward drums, as well as the pump and valve body have been rebuilt


Christopher Winter
Christopher Winter
1967 Sedan DeVille hardtop

savemy67

Hello all,

I was able to obtain a thinner rear selective thrust washer for my transmission.  While searching for the washer, I stumbled upon a tech article written by Randall Schroeder, a member of the Sonnax Industries technical staff (the link is below).  The article discusses clearances (other than clutch pack clearances) for the TH400, and points out that the GM information is lacking for some of the measurements.  Compared to the article, my Cadillac shop manual specifies two of the four clearances discussed.  So how careful does one need to be when rebuilding a TH400 for stock use?  If practicable, I tend to err on the side of thoroughness, so checking additional clearances seems like a reasonable thing to do.  I also consider how an assembly functions when operating, in order to evaluate the value of the extra effort.  In addition to the clearances discussed in the Sonnax article, I will also consider clutch pack clearances.

Photo 4376 shows the gear-train in my DIY holding fixture (the output shaft goes through a hole in the bucket).  The Sonnax article discusses how to check not only front end-play at the input shaft (photo 4250) and rear end-play at the output shaft (controlled by the washer I just bought), but also end play between the two planet carriers, and between the forward clutch hub and direct clutch drum (see article for photos).  The article did not discuss why GM did not include these additional clearance checks, but after reading the article, I think it is worth the time to double check these clearances.

Photo 4380 shows the reaction carrier (the front planet set) planet gears.  These gears are helical cut gears.  The planet gears in the output carrier (the rear planet set) are also helical cut gears.  Helical cut gears are used because they are quieter than straight cut gears.  Many high performance Powerglides and TH400s use straight cut gears.  The axial load (front to rear) on straight cut gears is relatively negligible, whereas on helical cut gears, there is a relatively greater amount of axial load.  As the helical gears rotate, the torque load wants to push the gear backward (or forward) in addition to rotating the gear.  Even though there is a planet pinion thrust washer for each of the four planet gears in each carrier, when the planet gears are pushing on the planet pinion thrust washers, it is conceivable that the carrier is subject to the thrust forces as well.  So, end play clearances are important enough to consider, as far as my rebuild is concerned.  The shop manual has a specification for the planet pinion thrust washers and mine were within spec.

Clutch pack clearances are also important.  Photo 4377 shows my direct drum with the clutch pack steels and frictions installed.  If clearance is too small in a clutch pack, there will not be enough space between the frictions and steels when the clutch is not applied.  This may allow excess heat to build up and could result in burnt frictions and contaminated fluid.  However, you will probably get neck-snapping shifts - for a few hundred miles.

If clutch pack clearance is too big, you may not get sufficient contact between the frictions and steels when the clutch is applied.  This condition can also cause frictions to burn prematurely because the frictions and steels are always slipping, thus generating excess heat.  You may feel this as a long drawn out shift between gears.

Like Goldilocks, there is a point where clutch pack clearance is just right - not too small and not too big.  Some rebuilders use a rule of thumb that there should be about .010" clearance per friction.  In the TH400, the forward and direct clutch packs use 5 frictions each.  The intermediate clutch pack uses 3 frictions.  So, the rule of thumb suggests I have .050" clearance in the forward and direct clutch packs, and .030" clearance in the intermediate clutch pack.

The Cadillac shop manual for my '67 TH400 does not specify what the clutch pack clearances should be.  The Automatic Transmission Service Group (ATSG) specifies .010" per friction, so the clearances should be as above.  In Ron Sessions "How to Rebuild and Modify the Turbo-Hydramatic 400", the clearance for the forward clutch pack is given as .030"-.070", for the direct clutch pack the clearance is .040"-.080", and for the intermediate clutch pack, .040"-.100".  Two different references with differing specifications for the same assembly is not helpful.  Although, for the forward and direct clutch packs, the ATSG and Sessions' specifications overlap.

One way to remedy this, as I mentioned above, is to consider how the parts operate.  The clutch packs work when hydraulic pressure is applied to a piston behind the clutch pack.  The piston compresses the steels and frictions.  The distance the piston travels can be measured for each of the clutch packs.  Photo 4374 shows a dial indicator used to measure the intermediate clutch pack piston travel.  Instead of hydraulic pressure, the piston is actuated using compressed air.  Knowing the piston travel, and the thickness of the steels and frictions, and the location of the snap ring groove in the clutch pack drums or case (the snap ring is the ultimate limiting factor in clutch pack travel), I can determine which of the recommended specifications is best for my application, or I can decide on a different specification.  I want this rebuild to be the only rebuild of this particular TH400.  I want the car to shift smoothly, like a Cadillac should.  I also want to get long life out of the transmission fluid.  All these factors need to be considered.

When I did my initial tear-down, the frictions in the forward and intermediate clutch packs looked OK.  The frictions in the direct clutch pack looked burnt (very dark brown with material flaking off - photo 4303).  When I reassembled the direct clutch pack and measured the clearance, it measured .005" which is too small.  The steels in the direct clutch pack measured about .093" thick.  Thinner steels (about .077" thick) are available.  I want to thank fellow CLC member Bruce Roe for sending me some thinner steels which allowed me to adjust the direct clutch pack clearance to a more reasonable .053".  Photo 4381 shows the thick and thin steels side by side.  The .005" clearance with all original steels and new frictions would have resulted in a burnt clutch pack at some future point - just like the original clutch pack was burnt.  One thing to keep in mind is that thinner steels will get hotter sooner than thicker steels, so if you mix thicknesses within a clutch pack, you may want to consider placing the thinner steels at the piston and or pressure plate end of the clutch pack where there is more metal to help absorb heat.

All clearances except output shaft and input shaft end play can be checked before the transmission is partially assembled.  The output shaft end play can be checked after the gear-train has been installed and the center support snap ring and bolt are in place.  This end play is controlled by the three tab washer that resides at the rear of the case.  Photos 4383 and 4382 show my set-up for measuring the output shaft end play with a dial indicator.  The shop manual calls for this measurement to be done in the vertical position.  With my recently acquired thinner washer, my TH400's output shaft end play is .008".  This is within the shop manual's specification of .003' - .019".  If you need to adjust the end play by selecting another washer, at least you only have to remove the center support snap ring, and the center support bolt, and lift out the gear-train in one piece.  Be sure you have a holding device as the gear-train weighs about 30 pounds.  This is a lot of weight to hold with your fingertips.  I removed and replaced the gear-train four times before I was satisfied everything was OK.

To measure the input shaft endplay, the direct clutch pack/drum assembly and the forward clutch pack/drum assembly, and the pump have to be installed in the transmission.  Input shaft end play is controlled by a selective thickness washer between the pump and the forward drum assembly.  Washer kits are available that have a few washers of varying thickness.  If you need to adjust the input shaft end play, the pump will have to be removed.  Removing the pump is easier than removing the gear-train because one does not install the pump o-ring until after the input shaft end play is checked, making the pump easy to remove.

The clearances on my TH400 are good to go for my purposes.  The next phase of my rebuild will be to install the remaining components (servos, valve body, solenoids, governor, speedometer drive, shift linkage, filter), button up the extension housing and pan, and paint the transmission.

Christopher Winter


(http://www.sonnax.com/articles/408-playing-with-transmissions-setting-total-endplay-to-prevent-th400-gear-train-failure)
Christopher Winter
1967 Sedan DeVille hardtop

savemy67

Hello all,

As the old saying goes - ninety percent of the work can be done in ten percent of the time, but the last ten percent of the work takes the remaining ninety percent of the time.

I have a few additional tasks to complete before finishing my transmission.  I worked on a few of them during the last few days.  One task was to clean and paint all the fasteners that hold everything together.  I used a wire wheel on my bench grinder to remove all traces of rust, and debris in the threads.  Bolt heads, nuts, washers, and retaining clips were primed and painted.  Conceptually, this is an easy task, but it is time consuming.  There were about 4 dozen fasteners that each required cleaning, priming, and painting.

Generally, if I remove a part, it gets cleaned and painted, so another task was stripping the drive-shaft, and sand blasting the transmission cross-member and transmission mount.  These parts were in turn primed and painted.

If you have been following this thread, you will know that I had to cut my transmission cooler lines because the lines had seized in the fittings.  Photo 4232 shows the cut ends of the steel cooler lines attached to the case.  What I didn't observe until I took the time to clean these parts, is that the fitting in the case is brass, but the fitting with the steel tube is steel.  When I disassembled and cleaned the parts, the bore of the steel fitting was corroded around the steel tube.  My plan to re-plumb the cooler lines is to install a short length of tubing into the case, and place a flare-union between the short length of tubing and the remaining length of tubing going to the radiator.  Photo 4390 shows some of the parts.  From left to right:  the case fitting, the short length of tube with its fitting, a fitting for the union end of the short length of tube, the union.  I cleaned the bore of the steel fitting and I will use anti-seize in the bore when the parts are assembled.  Note also that I left the union-end of the short length of tube un-flared.  This is in case I have to adjust the length at final assembly.  Not shown in photo 4390 is the remainder of the cooler line which is still in the car.  I had to put a fitting on the line, and then double-lap flare the tube while under the car (photos 4384, 4389).  The fittings here will be used to connect the lines to the union.  The lines and the cooler in the radiator will be flushed before they are connected to the transmission.  The lines for my '67 TH400 are 3/8".

Inside all TH400s is a solenoid that controls downshift when the throttle is mashed (kickdown).  Earlier GM transmissions did not have a solenoid.  Those models used a rod attached to the throttle linkage and connected to a valve in the transmission.  The kickdown solenoid on the TH400 is activated by a switch connected to the throttle linkage.  The switch energizes the solenoid which controls a bleed orifice in a hydraulic circuit.  Additionally, my '67 TH400 has the variable pitch stator in the torque converter. so there is another solenoid that controls fluid flow to change the pitch of the stator.  Both solenoids are inside the transmission case and are submerged/bathed in fluid.  After decades of use, the insulation on the wires that connect the solenoids to the connector on the side of the case, becomes very stiff and brittle.  Any handling, such as removal of the solenoids, may cause the insulation to crack.

Photo 4392 shows the cracked insulation on my kickdown solenoid's wire.  Photo 4391 shows that the wire was so stiff and brittle - like a piece of uncooked spaghetti - that the wire broke.  Hoping not to have a repeat of this calamity with the stator solenoid, photo 4394 shows that I was able to slip heat-shrink tubing over the original wire to reduce strain on the conductors, and to keep the old insulation from breaking off and falling into the fluid.  An ohmmeter showed the same resistance value before and after the heat-shrink tubing was applied.  The solenoid also worked well repeatedly when connected to a 12 volt battery.

I am the world's worst solderer, so I did not think I would be able to repair the kickdown solenoid.  Fortunately, just the other day I bought a '66 TH400, so I removed the kickdown solenoid from the '66 transmission.  Photos 4395 and 4396 show the solenoid before and after cleaning.  After cleaning, The '66 solenoid worked as well as the '67's when tested.  The resistance value is slightly less than the '67's, and the bleed orifice is a couple thousands of an inch different in diameter, but the connecting wire appears to be in good shape.

While I was under the car flaring the transmission cooler lines, since there is plenty of space without the transmission installed, I noticed a few other small jobs that I might tackle while the space is available.  Hope I don’t get too sidetracked.

Christopher Winter
Christopher Winter
1967 Sedan DeVille hardtop

savemy67

Hello all,

Finally, after numerous interruptions (I helped a friend completely redo her kitchen), and waiting on some parts, I finally completed the rebuild of my TH400 and installed it in the car (see my next post for the results)..

Nothing is ever easy in the old car hobby.  To wit, the photos below show the issues I had with the transmission oil filter.  When I bought the car, the previous owner supplied me with a new Fram transmission filter.  I noticed a number of differences between the Fram filter and the original style AC Delco filter, so I bought another filter manufactured by ATP.  Photo 4407 shows the three filters.  On the left is the ATP filter, made in Taiwan.  The middle filter is the Fram, made in China, and the AC Delco filter is on the right.  The AC Delco filter is stamped AC PF-160, and with a GM part number (5579822).  I don't know if the AC Delco filter is the original 1967 filter, but it seems to be a genuine GM part.  I searched the web for the GM part number and found a couple of eBay sellers with NOS AC Delco filters for $55 and $80 respectively.  The ATP filter and the Fram filter are in the $20 range.

A close look at the ATP and Fram filters shows how they differ from the AC Delco filter.  The ATP and Fram filters use steel tubes for the pick-up, and canister to case tube.  The AC Delco uses copper.  Photo 4409 shows that neither the ATP nor Fram filters' case tubes are chamfered.  The AC Delco tube is chamfered.  The significance of this is that the TH400 case is aluminum.  steel is harder than aluminum, so any irregularity in the ATP or Fram tube will likely scrape aluminum from the bore in the case whernthe tube is inserted.  The chamfered, copper tube of the AC Delco tube is more likely to conform to the bore without scraping any aluminum..

Another big difference between the ATP and Fram filters, and the AC Delco filter, is the location of the puck-up flange.  Photo 4412 shows a square against the AC Delco filter's pick-up flange.  The gap between the square and the canister body indicates that the pick-up flange sits lower in the pan.  In fact, the AC Delco filter is designed to touch the bottom of the transmission oil pan in the area of the "heel print" (photo 4417).  The heel print is the absolute lowest part of the pan, so if the transmission leaks, or the car is put through a violent maneuver, the location of the pick-up flange should allow the transmission oil pump to draw fluid without cavitating.

Photos 4413 and 4414 show the square against the canister body of the ATP and Fram filters.  Notice the gap between the pick-up flange and the square in  both the ATP and Fram filters.  Neither of these filters will touch the pan bottom in the area of the heel print.  Will this be a problem for my transmission?  Probably not, given how I drive.  The point of course is to illustrate the problem with aftermarket parts.  How much more would it have cost to make a filter just like the AC Delco filter?  Probably less than $5.  To make matters worse, I tried installing the Fram filter using a new o-ring.  Despite chamfering the edge of the case tube, I could not install the Fram filter.  I then measured the case tubes of all three filters with my micrometer.  The AC Delco measured .750".  The Fram measured .760", and the ATP measured out-of-round, averaging .747".  I installed the ATP filter with a new o-ring.

Half way through model year 1967, GM changed the filter style in the TH400 to a "broiler pan" type that is secured by a shoulder bolt that screws into the valve body.  The filter to case tube for this type of filter is usually plastic, so a precision fit is less an issue.

Christopher Winter
Christopher Winter
1967 Sedan DeVille hardtop