1956 Hydramatic: massive oil leak

[Roger Zimmermann]

Recently, I was contacted by a friend who is owning a 1956 60S, yellow (!). He said that he had recently a large oil leak at his transmission.
I got the transmission in my "shop"; I removed the flywheel housing, expecting a bad seal. The seal was indeed OK, but I replaced it anyway. Before I removed the flywheel housing, I discovered a long metal chip loosed on the front internal gear's hub. I looked everywhere; I found no trace from where the chip came.
After discussing that issue with the owner, I installed all parts back with new seals.
Yesterday, I had a phone call from my friend: the transmission was put back into the car, the engine started and then the people left, going home. The next day, there was a large puddle under the car.
Obviously, I will have to remove more parts to find where came the chip and if it can have an influence about the fluid loss. For the moment I'm myself at a loss, I cannot explain why and from where the fluid is coming.
Who has had a similar experience?

[fishnjim]

Keep us posted on this mystery. 
They can only leak out so many places, barring cracks, so linking the shaving to the leak is not a given.   Shouldn't be any unattached metal in there and how it stayed whole without being ground up but can't tell the dimensions from a photo without size reference.
They should investigate from under the car before removing again to see if possible to tell where leak originates, front, back, side, top, etc as it wasn't running when leaking out apparently.  Fluid leaves a trail. 
I always suspect the diptube on these, as it's removed and replaced when installing and they drain back high up on the stick when not running.  Good way to lose a lot of fluid fast.  Seals usually seep vs total failure..

[Roger Zimmermann]

The dip tube is definitively something to consider. I have a hard time to believe that this tube is suddenly leaking, but strange things can happen. I confess that I did not look at the O ring for the dip tube when the transmission was in my shop.
The oil cooler is also located under the flywheel housing. I let check it, it's totally leak free.
The owner is saying that the oil is coming between the plate closing the flywheel housing and the housing which would imply that the leak is at the seal from the flywheel housing. I have difficulties to believe at that possibility.
I found no crack at the housing, nothing suspect.
With a clean flywheel housing and fresh oil, I'm not confident to see a path.
That shaving was about 2" in diameter. Totally out of place when I saw it.

[signart]

It would help if it could be determined where the leak is coming from. The yoke on the drive shaft can be a source of a serious leak if it is worn or has a groove, even with a new seal, which I am sure you replaced. Just something to consider investigating. 

[Dave Shepherd]

How about cleaning  things up and put tracer dye in the trans, that should help pinpoint the source.

[Roger Zimmermann]

The leak is at the front, not the rear.
Of course, when the transmission is back to me, I will try to see the oil path. According to the owner, when the plate closing the flywheel housing was removed, some more oil came out.
Unless there is a mechanical issue, only two seals can be the source: the seal ring at the flywheel housing and the large o ring at the flywheel.
I see that I will have soon some detective work to perform!

[CadillacFanBob]

Roger, when transmission is put back into car, ADD DYE to transmission fluid (they have for engine oil, transmission, cooling system, and A/C system, and can be purchased at local auto parts store, and after car driven, if still leaks use ultraviolet light with transmission in car and you will be able to see where dye is coming from.

Bob

[Roger Zimmermann]

Well, thanks for that suggestion. I hope to find the leak without adding a dye because when the transmission is installed, it's not possible to see the real source as the fluid coupling is in the way. It can be that the dye will stick to the flywheel housing. The car is also at 100 miles from my shop...
In fact, I'm suspecting that an hard part has a problem I did not notice when I was working on it.

[CadillacFanBob]

Roger, do you have the Hydra-Matic specialty tools? If so please could you post a group photo of the ones you have for us to view?

Bob

[Lexi]

Yes, that would be something to see. Clay/Lexi

[russ austin]

That dip stick tube seal is about the worst design ever. I pack the top of the tube right below the flange with RTV gasket maker. I let it cure a good day before I add fluid.  No leaks for me.  Yes, I replaced the O ring and thought it would be good. It wasn't good and leaked.

[Roger Zimmermann]

I don't have many special tools. I will do that the next time I'm in my shop!
If the dip stick tube is slightly damaged, a leak is guaranteed!  On my de Ville, I had another O ring under the flange, and it would be compressed against the case. On my '56 Biarritz and on my ex-57 Brougham, I just have/had the regular O ring without issue.

[The Tassie Devil(le)]

Seeing as there are millions of these transmission Dipstick/filler tubes out there, not leaking, I would say that GM/Cadillac properly tested them.   Plus, GM never ever used any gasket sealer or RVT.   Just a bit of Vaseline or Transmission Oil to assist in inserting the tube.

For one to leak, either the "O" Ring is wrong size, or the tube is bent or cracked.

Bruce.

[Roger Zimmermann]

Today, I had to go to the store room/shop. I pictured the special tools I have.
First picture: on the left, the tool J-6121, front unit coupling cover removal. Before the purchase from that tool, I used a steel plate. It can be bent if the cover is not cooperative.
On the right, the tool J-6135, neutral clutch retainer. It's home made.
Second picture:
#1 is J-6282, front unit end play checking gage
#2 is the spacer number 1 to be used with that tool
#3 is J-6120 reverse drive flange retainer. Before, I used some wire
#4 is J-7577, reverse piston inner seal pilot, home made, used on 59-64 transmissions
#5 is J-6122, front unit coupling valve retainer. One is the "right" retainer, the others are made with brass.
Of course, I have the needed pliers for the various snap rings. All other tools can be superseded with some creative ideas!

 

[CadillacFanBob]

Roger, THANK YOU this is good stuff

1949 Cadillac Hydra-Matic at: www.weber.edu has a 5 part series YouTube video on Cadillac Hydra-Matic, the professor did an excellent job with this 1949 Cadillac transmission.

World's First Mass Produced Automatic Transmission - Part 1

Bob

[PHIL WHYTE CLC 14192]

Roger, THANK YOU this is good stuff

1949 Cadillac Hydra-Matic at: www.weber.edu has a 5 part series YouTube video on Cadillac Hydra-Matic, the professor did an excellent job with this 1949 Cadillac transmission.

World's First Mass Produced Automatic Transmission - Part 1

Bob

The 56 Hydramatic is a totally different as it was the first year of the Dual Coupling hydramatic, often called the Jetaway (I believe that's what the Oldsmobile called it?).
I have most if not all the Kent-Moore tools for the early Hydramatic, but none for the 56 on.
Phil

[Boss429]

Hi Roger:

Are you 100% certain the leak is coming from the transmission and not the rear main oil seal at the crankshaft? The location is exactly where you have described the transmission leak. Some motor oils, such as royal purple can look like transmission fluid until the oil gets some mileage on it the after a change.

Roger Mialocq

[Roger Zimmermann]

It was also my question to the owner. It's definitively from the transmission.

[Caddy Wizard]

Roger, that thing is not a "shaving" that has been cleaved off of some part due to rubbing or grinding.  The thing has a smooth surface -- it is a manufactured part.  You say it has a diameter of about 2 inches?  Isn't the front transmission seal about that size?  It could be a part of the old seal, perhaps a stiffener for the lip or part of the metal body that is covered by rubber.  Also, it looks to have a bluish color, which might be an indicator that it is a spring of some sort.  If you bend it, does it spring back into shape?  A shaving would not exhibit spring-like behavior.


The front seal on a regular Hydramatic (up to about 1955) can fail suddenly and can leak very badly.  On a 49 that I was working on for several years, I had replaced the rear (tail shaft) seal and then one day the front seal developed a horrible leak.  It went from not leaking at all to pouring fluid out terribly, all of a sudden. (the seal was original with about 70K miles and had never been replaced).

[Roger Zimmermann]

Well, Art, you may be right. The seal at the housing was like the ones I replaced on many transmissions, nothing special. It has the garner spring at the back as usual; as it's still in the garbage, I will have another look at it.
I don't have this "thing" anymore, but you are right, it was like a small strip of steel; a shaving would not look the same.
Anyway, it does not answer why the new seal should have failed after the engine was run for 5 minutes. The transmission is not yet back to me; that issue is for the moment on a back burner.