transmission upgrade

[Pat Rizzo]

I own a 1956 Cadillac coupe de ville. The car sat idle for over a decade. The trans works but restoring it is quite pricey and being that it isn't one of the best transmissions Cadillac ever made, I would like to install a newer model. Can anyone tell me if there is a trans that will bolt right up.

[Scot Minesinger]

There is no transmission that will bolt right up to the 1956 Cadillac w/365 engine.  A desirable transmission was not made IMO until 1964 with introduction of TH400.  So you will have to go with a new one made for the car IMO.

There are kits for 700 series (700R4 I think) trans that are a 4 speed, and that is probably what I would use if I wanted to change transmissions.  They are available with adaptors or they can be made if one is not available for your car.  It is made for older cars and includes an overdrive, which is nice.  I heard of a club member installing one of these on a 1962 Cadillac (390 engine - should be similar bolt up to yours) and another on a 1973 engine (472) modified Cadillac with nice success driving both all around the Country.

Overall it will likely be less expensive to just rebuild the transmission you have than to buy a new 700 series one and pay to have it installed.  Plus you have the headaches of all the interfaces with shifting(what tells car to shift down for passing and etc. and gear selector.

Modifications for budget purposes rarely work out very well on these older Cadillacs.  It is usually the most economical in consideration of all aspects including retained value to repair the original system.

[57eldoking]

I agree with Scot, the controlled coupling Hydramatic is a wonderful transmission that will give you many miles and years of service when rebuilt properly!

[TJ Hopland]

I'm not any kind of expert on earlier transmissions but what Scott says makes sense.   I was just looking at a swap project so I had an adapter page open so I looked at the Cadillac one and just the bolt up to the engine kit is $795 which apparently also includes a custom starter.   Likely a clearance issue is why the starter is needed.   One thing Scott didn't mention is drive shaft work.  You will likely end up having to have a custom shaft made which is not crazy expensive but still an additional cost.  Things like the shift indicator not working are an annoyance too.  IF you were putting in a aftermarket or later steering column or a floor shift no problem but if you want to keep the stock look you will have to get creative or live with the indicator sequence being wrong.  At least it will be the 'normal' sequence so less confusing than if it was the other way.   I hardly ever drive something that old so having reverse at the far end really throws me.  Also have to figure out how to get the speedometer to be accurate.  At least a 700 has fairly well documented info on what gears to get to get close. 

http://www.transmissionadapters.com/Pricing.htm

I just got a quote on doing a 57 Hyromattic and the shop told me that $1000-2000 is the typical range for one and that is me giving him the whole car.   He did say that things can get expensive fast if there is hard part damage like the torque converter.  HE said he recently had to replace one from that era and it was almost $2500 on its own.  Apparently most of these are an easily taken apart unit so they typically can just be cleaned and seals replaced unlike the modern ones that are welded together and usually just replaced.  Also got a quote on a 4L80e  that is $2500 out of the truck if nothing is broke so the 57 seems like a pretty sweet deal.

[Jon S]

There is no transmission that will bolt right up to the 1956 Cadillac w/365 engine.  A desirable transmission was not made IMO until 1964 with introduction of TH400.  So you will have to go with a new one made for the car IMO.

There are kits for 700 series (700R4 I think) trans that are a 4 speed, and that is probably what I would use if I wanted to change transmissions.  They are available with adaptors or they can be made if one is not available for your car.  It is made for older cars and includes an overdrive, which is nice.  I heard of a club member installing one of these on a 1962 Cadillac (390 engine - should be similar bolt up to yours) and another on a 1973 engine (472) modified Cadillac with nice success driving both all around the Country.

Overall it will likely be less expensive to just rebuild the transmission you have than to buy a new 700 series one and pay to have it installed.  Plus you have the headaches of all the interfaces with shifting(what tells car to shift down for passing and etc. and gear selector.

Modifications for budget purposes rarely work out very well on these older Cadillacs.  It is usually the most economical in consideration of all aspects including retained value to repair the original system.

Scot -

Having the original Hydramatic in my 1958 and having had a 700R4 in my 1984 Oldsmobile 98, the 1958 (IMO) wins hands down.  Much smoother and much more reliable.  I know the 1956's had their problems, so maybe the 700R4 is better than that one.

[TJ Hopland]

56 is an especially odd unit?   I thought by the 50's the Hyromatics were pretty similar.   

[57eldoking]

56 was the first year for the Controlled Coupling/Jetaway Hydramatic, a complete new design from the preceding original Hydramatic. 56 was a troublesome first year for this transmission and they often failed when relatively new. By 1958 most of these problems especially related to front sprag design issues were ironed out. However, every 56 unit still "alive" today have probably been rebuilt and updated at some point.

[J. Gomez]

The only “upgrade” that I’m aware of which others have done or are in the process of doing is installing a ’58 and swapping the tail end housing with the ’56.

What is perplexing with the tranny shop is their pricing for rebuilding these units. I too was quoted around $2K-$3K a few years back at several shops. However, once I questioned their process, availability of the special tools, reliability, etc. it was obvious the pricing was overinflated just because it was a “classic car”.   

A complete rebuilt kit from Fatsco is around $400 granted if other internal mechanical parts are needed it would be additional $$. If a legit shop charges $1K to $1.2K for their time plus the cost of the kit would be a reasonable price. Just my 2 cents…! 

The ’56 was a troublesome tranny as it was the first production year, since several modifications were made on following years the bad reputation stayed with the ’56.

Quoting other members who rebuild their ’56 with modern kits they are extremely happy with the performance, maybe they will chime in.

Good luck..!

[TJ Hopland]

I was quoted $600 for the 'soft' parts kit but there may be variations on the kits so a $200 difference does not seem that bad.  I think my guy mentioned that they often need the bushing on the input so maybe that was included in what he quoted me?   My guy also said he won't do one of these without the car.  Apparently there are some adjustments that need to be done with it in the car.   His shop and lot are full of old cars, I would say 3/4 of what I saw were older than 1970.  One car I could not even figure out what it was likely something European from the 60's.   It kinda looked like a Corvair.   We do have a huge classic car show coming up in a week or so so I suspect that is why his shop is extra full of classics. 

So 56-6x?  (when ever the THM400 came out) are overall similar?    Is it normal for you to feel the downshift and the engine rev/brake as you come to an easy stop like say a stop sign?  The 57 I just started messing with does that.  The owner thinks he remembers that being normal but admits his memory of driving one when they were new in high school was a couple years ago.

[57eldoking]

The 3-2 downshift and 2-3 upshift are quite more noticeable than the other shifts as it is the only one done by frictions in this transmission. What you describe sounds normal. The jetaway lasted from 56-early 63.

[wbdeford]

I too have a '50s Controlled Coupling Hydramatic that sat for many years, but still works.  I started to think, "What if it breaks?  I decided this was the perfect time to learn how they work.  I read the '57 manual until I understood the mechanism, bought a '58 transmission core + a Fatsco kit and rebuilt it slowly. 

So, now I have in my garage a rebuilt '58 transmission ready to go in my '58 SDV if the original one breaks + most of the special tools and a transmission jack--all for less than the cost of adapting a TH400. 

Just something to consider.

[dplotkin]

The only “upgrade” that I’m aware of which others have done or are in the process of doing is installing a ’58 and swapping the tail end housing with the ’56.

Having been painfully through this with my 56 Fleetwood I have the following advice:
The 56 transmissions were terrible. Cadillac very quietly replaced most of the early ones when the cars came in for service, owners may not have even known. The rest were rebuilt, sometimes more than once. There are probably no original, unopened units left on the planet.

Rebuilders then and now who know the unit install(ed) an updated kit of parts, trouble was in the front sprag, the neutral drum, the front coupling cover and the reverse cone. When the updated, better parts are installed these mixers become as reliable as the ones that followed. This in my view makes the 58 substitution unnecessary. A properly "fixed" 56 mixer will be just fine, I have one and went through this. In my case it took a new bell housing (bushing was wiped out) and valve body.

It is also worth mentioning that the transmission shop should have the car & not the transmission alone as verification of proper operation can only be made by carefully "dialing in" the adjustment of the TV rod.

Danny Plotkin

[TJ Hopland]

I have not looked close do these have a vacuum modulator or just the TV?   I know how touchy those can be with the 200's and 700's. 

Is the bellhousing bushing the one the torque converter rides in?  I think that is what the shop was describing to me that usually needs to be replaced on these and does not come in the kit so some people miss it. 

[wbdeford]

No vacuum modulator on a Controlled Coupling Hydramatic.  It only has four controlling inputs: engine speed, car speed, throttle position (TV), and shifter position.  No torque converter either. 

[TJ Hopland]

But there is a thing that kinda looks like a torque converter where you would expect to see a torque converter?   

If its not a torque converter that then explains why it does not just pull out like a torque converter does?   I have a sized engine with a trans still attached and have been told its not coming apart without having access to the flex plate bolts.   I have been told its been sized since the early 70's so its not going to be easy.  This project is way down on the to do list so it could be another 40 years before it happens just was wondering since this topic came up.   

[dplotkin]

The 56-64 Hydramatic has a fluid coupling (actually two, and the little one behind the big one is the "controlled coupling"). The big one looks like a torque converter and is nearly the same thing as a torque converter except for one thing, a torque converter has a stator in-between the impeller and the turbine and it is this stator that redirects fluid flow at low speeds and multiplies torque. This action is what permits a transmission with a torque converter to use a taller 1st gear and less gears overall, hence the Turbo 400 that replaced the subject transmission was a 3 speed unit, not 4, and had a much taller 1st gear. That is the advantage of a torque converter, torque multiplication allowing fewer ratios and simplified design. The disadvantage however is that at high speeds a torque converter is less efficient than a simple fluid coupling as the stator, which becomes inactive at cruise interferes with the fluid transfer between impeller and turbine. That is why Buick's Dynaflow was always berated for its lack of efficiency. It was a giant torque converter that at high speeds was not very efficient. It traded efficiency for smoothness. Packard, whose Ultramatic worked very much like a Dynaflow decided to add a lockup clutch to eliminate the inherent loss of efficiency, and by the 80's Chrysler, Ford & GM did likewise.

The transmissions that used simple fluid couplings, which include the original Hydramatic, the subject controlled coupling Hydramatic, and Mercedes Benz automatics of the 60's required a very short first gear to launch a heavy car as they didn't have the torque multiplication afforded by a torque converter. The first gear was so short that a total of 4 ratios was required, and that is why this type of transmission is generally a 4 speed design. The bennifit is that at cruise the non-torque converter transmissions are very efficient. Their fluid couplings actually stall (lock) and there is virtually no loss.

The original Hydramatic was efficient but overly complicated and dependent on intricate timing of band and clutch applications. They lurched and were far less smooth than Buick's Dynaflow, Chevy's Powerglide or Ford & Chrysler automatics, all using torque converters. GM decided to smooth out the old Hydramatic by adding a second fluid coupling and flushing or filling it to accomplish all but the shift from 2 to 3rd gear. Its engineers wanted to add a third coupling to make the thing as smooth as molasses but the accountants wouldn't allow it.

By 64 it was time to ditch the Hydramatic and go to Torque converters to be competitive with Chrysler's excellent Torque-Flight, and to a lesser extent Ford's CruiseOmatic, and so Buick designed the Turbo 400 which the Hydramatic division ended up producing for GM and several foreign makes including jaguar and Rolls Royce.

Dan

[TJ Hopland]

Thanks for the detailed description and comparisons.  I never expected to work on one so have never really paid attention to them before now.  These are 4 speeds? But one of the shifts you just don't feel?   And you only get 3 forward options on the shifter?  Or have I not been paying attention and there is 4?   I was thinking other than the order being different the indicator said P D D L R.   D D L Seems like how Cadillac did it till OD came out in the 80's?   Vs other GM's that did D 2 1?   Doesn't Cadillac owners manuals refer to L as 'parade gear'?     

So the large fluid coupling must be the thing the shop said can usually be cleaned and re sealed but if its been damaged is $2500 on its own and not stocked by just any supplier.   How is it removed from the trans?  Has to be disassembled via bolts in the front if the unit?  After that is out I assume the trans comes apart similar to most autos mostly from the engine end?   I'm not planning on taking one apart myself just wondering.   

[dplotkin]

Yes they are 4 speeds, so they shift 3 times once placed in drive. One detent to the right of drive will hold the transmission in 3rd, 2 detents will hold it in 2nd. The shop manual has a detailed exploded diagram of the transmission and shows how it comes apart. I have .pdf files of the 56 unit I can share with you if you provide an email address.

The shifts that you do not feel much are 1st to 2nd, which is dumping the front coupling, and 3rd to 4th which is filling the front coupling. By front coupling I mean the little coupling behind the main fluid coupling. During these shifts no friction elements are applied or released and that's why they are so smooth. The 2nd to 3rd shift is slightly less gracious in that it is a friction shift and there is a steep ratio difference between the two.

Hard parts for old transmissions like this are expensive and in some cases hard to find. That's why when one of these begins to fail it is unwise to keep using it and risk chewing up hard parts. On the controlled coupling Hydramatic, the usual failures are the front coupling cover seal, spaghetti seal, the front cover itself (they crack) or the rear unit clutch. There is only one band in this transmission and it does not hold against torque so they don't usually cause a problem nor can they be adjusted as for example the bands on a Powerglide, which can be made to function like new again through adjustment.

Dan

[wbdeford]

Great summaries, Dan.  Just a minor correction on the 1 -> 2 shift (and while I'm at it, listing the other shifts, too)

N -> 1 applies the neutral (friction) clutch
1 -> 2 fills the fluid coupling
2 -> 3 dumps the fluid coupling and applies the rear (friction) clutch
3 -> 4 fills the fluid coupling again
4 -> 3 dumps the fluid coupling
3 -> 2 fills the fluid coupling and releases the rear (friction) clutch
2 -> 1 dumps the fluid coupling

The band exists for one purpose only: engine braking.  It is applied when the shifter is in L.

Yes they are 4 speeds, so they shift 3 times once placed in drive. One detent to the right of drive will hold the transmission in 3rd, 2 detents will hold it in 2nd. The shop manual has a detailed exploded diagram of the transmission and shows how it comes apart. I have .pdf files of the 56 unit I can share with you if you provide an email address.

The shifts that you do not feel much are 1st to 2nd, which is dumping the front coupling, and 3rd to 4th which is filling the front coupling. By front coupling I mean the little coupling behind the main fluid coupling. During these shifts no friction elements are applied or released and that's why they are so smooth. The 2nd to 3rd shift is slightly less gracious in that it is a friction shift and there is a steep ratio difference between the two.

Hard parts for old transmissions like this are expensive and in some cases hard to find. That's why when one of these begins to fail it is unwise to keep using it and risk chewing up hard parts. On the controlled coupling Hydramatic, the usual failures are the front coupling cover seal, spaghetti seal, the front cover itself (they crack) or the rear unit clutch. There is only one band in this transmission and it does not hold against torque so they don't usually cause a problem nor can they be adjusted as for example the bands on a Powerglide, which can be made to function like new again through adjustment.

Dan

[Roger Zimmermann]

Well explained William!
To Dan: once the transmission is separated from the engine, there is a cover with the teeth for the starter motor. This cover is attached with a number of nuts (don't remember how many as the earlier transmissions had more than the more recent ones); once the cover is removed, the remaining parts are held in positon with clips. Remove one clip after the other and everything is coming out. It's a very nice mechanical set-up; therefore I have some fun to overhaul these transmissions.