Transmission leak question - 1967 Eldorado

[Varooom]

Transmission leak question- I recently removed and serviced the lower transmission pan on my 67 Eldorado. I still have a leak at the back of the transmission so I jacked it up and see fluid leaking from the back between the pan and big rubber cover that goes over the rear of the transmission.

This cover is soft and leaks easily when I just push on it. How much fluid is supposed to be back in there? I mean I do not see a way to fix this leak without pulling the transmission. Fix?  Ignore? Insight appreciated.

[Cadman-iac]

  Dan,

Under the rubber you mentioned is another pan looking piece that covers the chain drive from the converter to the front pump and input shaft. The rubber is there only for noise suppression.
I don't believe that you can remove the chain cover without first dropping the transmission. Your service manual should explain what is necessary and if it's possible.
It sounds like the cover is leaking and that rubber piece has been catching it.
 I just looked at my 72 Eldorado parts car and it does not have any rubber cover over the chain cover. That may be something that the engineers thought would be necessary for a problem that never occurred?

Rick

[bcroe]

They soon dropped the noise cover and built the
TH425 with just the metal chain cover.  I never
could hear any noise. 

I agree it is next to impossible to repair that
common leak until the trans is pulled.  That cork
gasket is not up to the job, with inadequate area
to seal against at the bottom (just where it is
most needed).  The GMC motorhome owners and I
have used a whole tube of VALCO to glue the cover
on, no more leaks. 

That is a switch pitch trans, hope that is working for you.
good luck, Bruce Roe

[Varooom]

The GMC motorhome owners and I
have used a whole tube of VALCO to glue the cover
on, no more leaks.

And the glueing was done with the transmission OUT of the car I assume?

[Cadman-iac]

And the glueing was done with the transmission OUT of the car I assume?

 I'm curious to know that too. In the motorhome chassis it might be possible to access cover while the transmission is still in place.

 Only Bruce will be able to answer that for sure.

[The Tassie Devil(le)]

Okay, so which Bruce are you referring to?

In my case, the gasket can be replaced with Loctite 5900, which is compatible with all Transmission and engine fluids, and once applied, will never leak.

It is imperative that the body and cover are clean (I use Brakeleen), and do not over-apply the sealer, as you don't want it oozing out into the transmission where it cannot be cleaned up.

Don't overtighten as this distorts the cover flange, and wait till the sealant has set before filling the trans with fluid.

I use two long 1/4" Whitworth metal threads and cut off the head to act as a guide to assembly.   Don't want any sealer getting in the wrong place.

Bruce.

[Cadman-iac]

 BCRoe actually, since he's the one that brought up the motorhome reference.

[bcroe]

I think you need to get that switch pitch trans
out of the car to remove (and throw away) that
noise cover, get everything cleaned up, and get
the surfaces horizontal (instead of standing
the car on the front bumper.  Several sealants
will work, a couple already listed.  We put a
layer on the trans and pan, wait a few minutes,
then put the rest of the VALCO on the trans and
put it all together.  Follow the guidlines from
Tassie Deville.  I do not know what is possible
in a GMC motorhome. 

If the trans has never been out, it ought to get
an inner and outer seal refresh, possibly reuse
the hard parts if moderate mileage.  Avoid a
damaging failure when a clutch fail later. 
Bruce Roe