The front unit coupling is stuck; no more!

[Roger Zimmermann]

For those who are familiar with the 1956 to 63/64 Hydramatic transmissions, a component is well known: the front unit coupling, which is like a small fluid coupling. Either with tangs or splines, it is mechanically connected with the race from the oil pump.
Recently, I began to overhaul a 1956 transmission. After the flywheel housing is removed, the front unit coupling can be slide out of the transmission. Not this one! Something is preventing the unit to come out. I can push, pull, used a slide hammer, nothing. It's like the hub from the coupling is welded to the race...
I see just one method: destroy the front unit coupling until I can unscrew the oil pump and hopefully slide out the pump and the remains of the coupling.
Has someone a better idea?

[Cadman-iac]

  Roger,  you may be on your own here. I've rebuilt a few 400's and 700R4's, but neither of those are anything like the Hydramatic. And folks like you are few and far between.
 All I can offer is best wishes and good luck.
 Maybe one day I'll get up enough nerve to try rebuilding one of those, but not now.
 I hope you can figure out how to remove it without needing another as replacement.

 Rick

[Roger Zimmermann]

Thanks Rick! I have two solutions: to destroy the front unit coupling or the case! As I have replacements for the front unit, the choice is quickly done. Just for the fun, I'll do pictures about the rescue...
I don't want to touch earlier or later transmissions: it's not with 78 year old that I want to open a repair shop for transmissions. I have enough to do with the range I'm doing: a third one is in the queue for this year...

[Poncholover]

A manual may be of use. I tried to pull the fluid coupling off of a '60 and it seemed like 1 snap ring after another.
There is something holding that thing together and outsmarting it is likely you only option...
let us know what you find!

[Clewisiii]

https://www.classichydramatic.com/

Contact this guy to see if he has any ideas. He has been very helpful with advice

[Dave CLC#16900]

I spoke with the guy from Classic Hydramatic, he is indeed helpful on the phone.  Disappointed he moved further East (North Carolina) though.  He was in Michigan until this year.  Looks like he overhauled his webpage too!

[CadillacFanBob]

I do not have any helpful information to help

BUT I feel you have one strange beast of a problem that is not encountered very often, and I feel if anyone can resolve this problem it would be you Roger with your diligence.

Maybe @Lexi views this he will chime in as he is another "56" boat load of knowledge on these vehicles

I will stay tuned for the answer

Bob

[J. Gomez]

Roger,

Could the front oil pump sprag be the problem blocking the front unit coupling from sliding out from the front pump? Or the tangs (since is the 1956 unit) on the front coupling are stuck on the front oil pump rotor?

Just a while guess..! 

[Roger Zimmermann]

Over the years, I overhauled between 30 or 35 such transmissions. Never had that issue. I suppose that the tangs are stuck to the front sprag inner race from the oil pump, like Jose is mentioning.
The driving assembly can be moved on the shaft maybe 5 mm and by turning it in both directions, the tangs from the front unit cover are doing the usual tone by touching the cavities from the oil pump rotor. This is not where the problem lies but, as described above, the driven torus assembly cannot be moved in relation to the case.
I will not do any call phone to the US. As per a very recent experience with a call, I just understood...nothing. In some parts from the US, people have a very strong accent which is not understandable by my poor ears!

[dplotkin]

Roger:

My 56 and 62 Hydramatics were rebuilt by the most knowledgeable person on the east coast of the US. Steve Peluso.

Tell him Danny Plotkin sent you. Tell him via email your problem and he will tell you what to do.

(508) 478-8900

stevepelusoautocare@hotmail.com



Dan

[J. Gomez]

Roger,

Just a crazy idea  , not sure if you can do it in your shop..!

Let gravity do the work for you. 

If you still have the front coupling with the transmission case, wrap a strap around the front unit coupling cylinder.
Hang the complete transmission from the strap, this will allow you to use the weight of the transmission to maybe force the coupling to come loss. This would also can give you a way to rotate the transmission case while keeping the coupling stationary and tug the case left and right to force the coupling off.

Again just a crazy idea but  , if the coupling is stuck in the front pump maybe this will force it out.

[Lexi]

Maybe @Lexi views this he will chime in as he is another "56" boat load of knowledge on these vehicles

I will stay tuned for the answer

Bob

Thanks for the vote of confidence Bob! Sadly, transmissions are not my thing. As a young-un I did not have the theatre or resources to properly remove and conduct servicing, so I did not learn much about them. Truth of the matter is that Roger has probably forgotten more than I know about these transmissions. I will scour my data for answer but unlikely that I will be able to assist. As Roger is indeed one of the "Cadillac Gods", if he doesn't have an answer we are indeed in muddy waters! Clay/Lexi

[Roger Zimmermann]

Thanks to all for the multiple suggestions. I may write an email to Dany Plotkin; what can I loose?
Jose: good suggestion, but the surface to wrap a belt or a rope to the front unit coupling is rather small: have a look at the picture (it's an older picture); I may weld another nut on the front unit to have a better attaching point.



I used this solution years ago: during a prior repair, one long screw was used to attach the oil pump cover where a short one is mandatory. The result was that the oil pressure regulator valve was stuck into its bore by the crushed cast iron. By hanging the transmission to the regulator spring, the valve came out after puling and shaking the whole transmission! It could be the case here...

[Roger Zimmermann]

This morning, I contacted by mail Mr. Peluso. Who knows, he had maybe the same situation once!

[Roger Zimmermann]

He is the answer from Mr. Peluso:

In 40 years, I have never had this happen to me.

Maybe cut the torus in half and see what you can see?

I am sorry but I have no other suggestions, besides what you are going to try.

[60eldo]

I have my old one here 1960 did you need a pic of it? Will that help?

[Roger Zimmermann]

It's kind from you, but I don't need a picture. After 30 or 35 overhauled Hydramatic transmissions, I know how the front unit coupling is looking like!

[dn010]

Maybe try to heat it up to see if expanding the metal does anything?

[Roger Zimmermann]

Dan, it's not a good idea: there is still a bit oil into the assembly and the place I suppose its locked is into the oil pump, too far away to be efficient. And most of all, I don't have anymore the welding system with two bottles (don't know the name in English).
I will the next few days weld two more nuts on the front unit and use an heavier puller.

[Roger Zimmermann]

This afternoon, I welded 3 steel corners to the driving torus and used a good puller. After a while, by hammering the torus, the assembly came out. It was like I expected: the tangs at the driven torus shaft broke, but the car could still be driven! The sole complain was no engine braking in D3.
The bronze thrust washer engaging with the clutch plate was also broken.
Sorry, I forgot the camera, will do pictures soon!