Overhauling a '57 Hydramatic

[Roger Zimmermann]

For 2 days, I got a '57 Brougham transmission to overhaul; it's the fourth Hydramatic transmission for this year! The car belongs to a former member from the defunct Eldorado forum.
I'm showing some pictures after the main elements were removed from the case. It seems that this transmission was never overhauled before; the color from the aluminum parts (and others) proves it. The transmission had a strange shifting behavior; when the cover from the front unit coupling was removed, the seals were hard like glass. The frictions are pitted, a bushing is to be replaced, but for the moment, I saw no major failure. If there is some interest for that topic, I will continue it as the cleaning/assembly begin.

Edit: sorry, there is a picture which does not belong to that, but I don't know how to remove it. Bruce maybe?

[The Tassie Devil(le)]

Done.

Bruce.

[Roger Zimmermann]

Thanks Bruce! My 1:12 scale Mark II model definitively does not belong to a Cadillac forum!

[savemy67]

Hello Roger,

Do you know how many miles are on the transmission?  I would be interested in seeing photos of what you found that was damaged or worn.

Christopher Winter

[Roger Zimmermann]

If the info I have are correct, the car has about 40 to 45'000 miles only. The steel plates in the transmission are in a very good condition, the frictions are bad probably because the first oil replacement was done 3 years ago...
As there is interest (also from another forum), I will document as good as I can during the overhauling.

[59-in-pieces]

Roger,
I for one would be very appreciative if you would continue posting pictures with narrative as you rebuild this trans..
Have fun,
Steve B.

[6262]

Roger,
I for one would be very appreciative if you would continue posting pictures with narrative as you rebuild this trans..

Me too.

[Roger Zimmermann]

Thanks! I will do. You must know that there are some differences between all those years; the main one is that the rear oil pump was used from 1956 to 1958. Consequently, the reverse clutch was modified on later transmissions, but the principe in all those tranies is the same.

[Roger Zimmermann]

Now, the "fun" begins with the cleaning of the case. Fortunately, I have a cleaning machine, it makes the life easier. The case (picture 11) is now ready with the assembled parking brake system.
Then, I pulled the front unit cover with the special puller. On the picture 12, both exhaust valves are already removed. You can see at the pictures 13 & 14 the remains of one seal, hard like glass. No wonder that the shifting was questionable.
The front unit coupling has 4 seal rings, pictures 15, 16 & 17. On all transmissions I overhauled, this one has the less marking on the driving torus, picture 18. It could be that the man welding that part fell asleep, have a look at one of the vanes.
The picture 19 is showing the undamaged coupling cover compared to another cover I have, picture 20. I saw worse on some transmissions...

[Roger Zimmermann]

After all is cleaned, I put both new thin rubber seals, one new internal seal ring and I installed the cover; this is the job which is the most critical as one or both rubber seals can be get damaged during installation. Once the snap ring retaining the cover is installed, I tested the assembly with compressed air at a rather low pressure, with the help of a oil pump cover. If the job is correct, the cover is almost jumping out, picture 21.
I'm now cleaning the reverse drive flange, with its selective thrust washer, picture 22. As I noticed no unusual play before removing all parts, I let this spacer. I'm using vaseline to avoid that the washer get dislodged during the next few operations.
I cleaned also the rear unit drum and the output shaft and I assembled those parts, picture 23. To avoid that the washer get dislodged, a special tool can be used too, picture 24.

The assembly is now on the bench with the output shaft down, allowing the installation of the needle bearing. Some transmission oil is added.

To be followed...

[savemy67]

Hello Roger,

Do you have a hot tank (completely encloses a part and subjects the part to high pressure heated solvent) or do you have a parts washer (an open tub where solvent is pumped through a brush)?

On youtube, there is a fellow in the Netherlands who rebuilt his '58 Oldsmobile's HydraMatic.  the vanes in his front unit coupling were totally destroyed - like a bomb detonated in the coupler.  I think it unlikely that the fluid could cause this type of damage.

You have rebuilt several of the controlled coupling HydraMatics.  What is your theory as to why these units failed?  Too much end play?  Inherently flawed design?  Poor quality manufacture?

Replacements are expensive - $300 - $400 dollars - so one would like to be sure that something other than the coupler is not going to result in damage to a replacement coupler.

I was looking at the newspapers you had under the various parts.  Some were in German, and some were in French.  I recall French is your native language.  Do you speak German as well as English?  Tres bon!  Zehr gut!

Christopher Winter

[Roger Zimmermann]

Hi Christopher

Thanks for your comments. I have a parts washer; sure, a hot tank would be more efficient, but I'm not overhauling transmission as a trade! Before I had this parts washer, I cleaned the parts in a large container using thinner as a cleaning agent...
I never had a front unit coupling destroyed like this '58 Olds, but, going to a friend in France, he showed me a coupler destroyed in a similar fashion. I suspect that either a vane broke at the weld or because of fatigue and then it's going fast.
Usually, transmissions coming to me are still working but not so well, usually because the rubber seals are too old; I have seldom major failures. I had some cases where the large snap ring retaining the cover's coupling gets dislodged from his groove and the cover is pushed out toward the oil pump. Another major failure was on a '56 transmission when a tang at the front sprag inner race from the oil pump and/or the engaged tang at the driven torus shaft broke. This was a major flaw and many transmissions were modified to have splines at both parts.
One of the transmission I did this year had a compete destroyed reverse cone and warped neutral clutch discs, like somebody went from R to Low with a lot of power, but the car drove, even if the reverse was not so efficient!.
A transmission I saw in France had broken tangs at the front internal gear. I suppose that the transmission was previously overhauled and a wrong intermediate shaft snap ring was used. That snap ring broke, allowing the driving torus assembly to have too much play. Maybe other factors were also involved because I don't know why the transmission was previously restored.
Yes, my native language is French but I can also read and speak German, but not perfectly. It's really an asset in Switzerland to be able to read/speak a second language and, without English knowledge, I could never had the job as a District service manager for GM US cars.

[V63]

I had experience with a 1949 hydromatic that had 23,000 miles on it, this fleetwood was a time capsule. Shortly after putting it in service again the transmission was failing. My first thought was a complete fluid change and cleaning valve body. When I removed the pan...the fluid was like Jello. I scooped it out with a spatula.

The pump starved for oil and the pump was toast. A Total rebuild followed.

My ‘GUESS’ was that this fluid was made with original  whale oil that was banned in 1973?  Moreover , likely the original fluid from 1949, the car certainly represented as such a possibility.

[Roger Zimmermann]

Interesting...I heard about that whale oil, but don't know if the Dexron I was still based on that. The '56 transmission I cited above still had his original transmission oil. It was still liquid but stank like an old engine oil and was very dark.

[V63]

Off the top of my head, I would be tempted to think that  DEXTRON name may have originated with the new mandated fluid of synthetic whale oil?

[59-in-pieces]

For those of you who seem to know a great deal about the fluids, were the earlier fluids actually made entirely or partially of whale oil.
If so, why weren't oils of the time used - a question of viscosity.

Please don't tell me I have fallen victim to a "left handed Monkey Wrench" story.

Have fun,
Steve B.

[Mike Josephic CLC #3877]

The original Dexron (it's DEXRON, no "T") fluid, like its
predecessor Type-A/Suffix-A, used sperm whale oil as a
friction modifier. 

That continued until around 1970 and was stopped for
two reasons (1) the "endangered species act" and (2)
sperm whale oil could not hold up under the higher
temperatures encountered in the newer transmission
designs.

Mike

[Roger Zimmermann]

Usually, I'm working each second day, to spare my old bones! Today was some cleaning and further inspection planned. I began with the rear pump and reverse clutch. What I found was not pleasant: I did not expected to find the seals like new, but those were really out of order. I'm wondering if the reverse was still functioning, picture 26.
By looking at the rear pump body, I saw that one dowel is missing from new! Will GM still honor the warranty? Have a look at the picture 27.
By looking at the piston, there are marks at 2 places, the third hole is not marked at all. The dilemma is now by the owner: search a complete part or install as is?

[Roger Zimmermann]

I just got a call from the owner regarding the missing dowel: as the transmission has about 40'000 miles and no damage could be seen at the rear clutch and associated parts, I will assemble that part again as is.

The next job was the front oil pump. This time, there were no bad surprises, everything is almost as new. The overrun clutch was bad and I had one available. After cleaning, the assembly began with the installation of a new bearing into the pump cover, picture 28. I cleaned also the rotor and vanes, picture 29. Now it's time to assemble the cover; there are 4 bolts and 1 is shorter as the other 3. This short bolt is coming in this position, picture 30. If a longer bolt is installed in this position, say good bye to the pump! Now, the pump is assembled again, picture 31.

By looking at the other parts, I found one bad bushing at the driven torus assembly, picture 32. Of course, this bushing will be replaced; this is now the next task: order the seals, clutches and gaskets.

[Roger Zimmermann]

Yesterday was a cleaning day, plus some assembly. I began to remove the rear clutch piston by using some special tools and not the ones described in the shop manual, see picture 33. I did plans long ago to build the correct tool but this unusual method is working well...
After cleaning and putting 2 new rubber seal, the rear clutch piston assembly is ready, pic 34.
I did the same for the central bearing support; this one does not require a special tool. Then, I began the cleaning of the valve body. 1956 and 1957 transmissions have a tiny ball, it's wise not to loose it.
As you can see, the valve body is dirty, pic 35; you can see the ball on picture 36. After 2 or 3 hours, the valve body is ready (pic 37); all valves are free in their bores and I did not loose the ball!
I noticed that there were changes in the coupling valve body, compared to the shop manual: there is no spring for the overrun clutch valve and only one spring for the coupling valve. Those changes are not documented in the various service bulletins. Usually futile things are described in length, but important changes are not mentioned. Strange.