CamminC5

I noticed a leak there and from the left axle seal after I finished my clutch/brace install. I cleaned the area between the trans/diff and smeared on some red RTV. It's fixed for now, but I plan on pulling the trans/diff this winter and fixing the seals and throw in some c6z shafts...

Dixiecrat

Thanks guys, never to old to learn.

marc a

So here is what my tranny/diff joint looks like. No fluid is coming from above, all from the seam. It takes less than ten minutes for a drop to appear at the seam after cleaning.

So, am I looking at replacing the large black o-ring?

Thanks in advance.

Marc

Bill Curlee

Yep,, thats the result of leakage past the big O ring seal. Are you SURE that the trans to diff bolts are properly torqued

Give that a look first.

Bill

Bill Curlee

Is it 90 weight smelly gear oil or red ATF?

You need to be sure!!

The only thing in that void between the trans and diff should be gear oil.

If its ATF,,, something else is wrong!!!!!

marc a

Thank you Bill.

Yep it's 100% red ATF. I took another look this evening and the leak is at the seam between the transmission and extension housing the factory silicon cement must have gone bad.

Either way everything is coming out to get resealed.

Marc

Bill Curlee

The transmission tail shaft has a SEAL that keeps the Transmission ATF inside the transmission. The Manual MN-6/MN12 Differential does NOT have a bulkhead that keeps the 90 weight inside the differential.

90 Weight SHOULD be the only fluid at that seam

The Automatic Transmission and differential should be DRY at that union. The A4 differential has a bulkhead with a seal that prevents the 90 weight from that void area. The transmission also has a seal.

Try this. Pop out the fill plug for the MN-6 transmission and SMELL it. It should smell like ATF. If it smells anything like 90 weight, you have issues!

Bill

marc a

Sorry, I'm a little slow tonight. Went back out and looked at the fluid drip. Although the fluid looks red, it's not "100% red ATF" It has a slight tint and the tell tale smell of 90w.

Thanks for your patience.

Marc

marc a

Drained the transmission to start the removal process and here is the color of what came out. Viscosity of old is same as new.

Brand new Mercon III next to it.

Is this the normal color for the fluid assuming that it has been in there for a while?

Marc

enoniam

Looks like some well used ATF to me.

marc a

Should have mentioned that the car is manual.

Thank you . . . . the next batch will never get that dark

Socko

That is not the trans to diff junction which is how you have trans fluid not diff fluid leaking. Thats where the 5-6-R gears live.

Hopefully its pushing out the vent, if not the trans is coming out. Don't overfill it, it will push out.

The red arrow is yoru leak, the green arrow is where the diff joins the trans.

Mr. Jones

The red arrow is yoru leak, the green arrow is where the diff joins the trans.[/QUOTE]

I thought this seal was RTV not a gasket. Can someone confirm?
If this is correct I have a method I used to seal this area-PM me and I will provide details. I did a repair on my car about 6 years ago no new leak and did not drop the trans/diff.

Socko

You are correct, its an rtv joint. the between the diff and the trans is not that joint, and is where the oring is.

1999c5stroked

I thought this seal was RTV not a gasket. Can someone confirm?
If this is correct I have a method I used to seal this area-PM me and I will provide details. I did a repair on my car about 6 years ago no new leak and did not drop the trans/diff.[/QUOTE]

I have this issue right now. Just bought the car and don't have the funds to pull the trans can Toulon me federalist how you fixed yours

SaberD

It's an rtv joint. no gasket in there. sorry for the confusion.

Mr. Jones

Wow an old post revisited.

clean the transmission and identify exactly where the leak is.
Drain the transmission, loosen the bolts between the trans and diff. (only a few turns and you should see a gap open).
spray brake cleaner in the opening to clean and let it dry.
Now apply RTV where it was leaking.
use a putty knife to force it in the opening.
Now close the drain hole and attach a small shop/house vac to the fill hole. You will need to tape some small hose to the vac. and adapt it to fit the fill hole tight.
you don't need to much vacuum here, a small rechargeable vacuum works fine.
You should see some of the rtv being pulled into the opening.
you can turn the vacuum on and off the pull a small amount in don't over do it.
Once you have RTV in the opening tighten the bolts and let is sit for an hour or two.
Fill the trans and hopefully it works for you.
Still working for me.

Bill Curlee

That procedure is from the McGuiver Engineering Institute.

BC

Vetteman Jack

Closing this old thread.