Weeping over T84 weeps

[ghiltgen]

My T84 is leaking, sm puddle on floor, maybe 2 tablespoons in amount, consistently. I removed the trans and inspected everything and it is coming from the front bearing cap area. I removed this and resealed the bolts and used rtv on the bearing cap and still have leakage. However, I would say that at first after I did this there was no leak but it started after about 50 miles of driving.
When the bearing cap was removed I noticed the felt ring was very saturated, so now I am of the conclusion that bearing cap chamber is filling with oil and it’s draining out past the felt. I wondered if it was too full of oil because I filled it from the top with the tranny cover off, so I brought the level down to the fill port, but still no joy.

Should the outer bearing surface of the front bear be sealed? I believe also I have heard of people filling the little return hole that theoretically lets oil back into the case. I am using sealed front bearing from Ron.

[dpcd67]

Read all this and all your questions will be answered. Your jeep will still leak, but at least you will have 4 definite reasons why it does.
That seal is cork; I have seen the felt ones but don't trust them.
Also make sure the transmission is not getting over filled from the transfer case. Oil can migrate through unless you have a sealed output bearing in.
viewtopic.php?t=185225

[Joe Gopan]

I always use only the OEM cork seal, and keep an extra or two as the seal can split if one is not careful. I squirt lube on the MD Gear splines and use the M.D. Bearing retainer to carefully push the cork in place. If you are not careful, the seal will split. The GI Mechanics did this the same way,
That felt seal is only for the T-90 I installed a NOS OEM 640018 cork seal in my MB's T84 50 years ago-no leaks yet.

Again, these gearboxes are nor 75+ years old and must be checked for wear that will cause leaks. An egg shaped countershaft hole at the front will have just enough play to allow a leak at the bellhousing.
Good T-84 Cases are rare at this late date.

[ghiltgen]

Thanks!

[JAB]

I don't know the history of this transmission but I had one that was missing the cap/thimble that goes over the shift rail and it had the same symptoms.

[W. Winget]

Mines leaked for 40 years, I park her in a grassy area after driving to let things drip off before going into the garage, then there's cardboard...
I think I have filled it twice maybe three times in all those years.
When it stops dripping, or starts to feel different during a shift I will check the level and usually top it off through the shifter vs side filling it.

The Army and "collectors of one or two perfect vehicles" can afford swapping labor and parts for a Class I (wet) or Class II (forms drops) leak, lifes too busy unless it's a Class III leak (dripping).
V/R W WInget

[ghiltgen]

Turned out to be 2 issues. Once I took out the tranny and transfer case as one unit I could see the major leak was from
the seal on the front of the TC. So that got changed out. I only had 700 miles on that seal and the felt piece was ripped to shreads, possibly because I didn’t oil it the first go around. This time I oiled it to be able to push it into it recess more completely which I feel good about.

But also the cluster counter shaft orifice had a leak from the front of the box. I left the oil in the gear box while taking it out so as to see where the problem was. It was a “WOF NOS” case supposedly, but in reality I think I was a Chinese mystery box. It didnt have WOF on it and it had a round almost starburst symbol on it. I saw from other threads that no one really knows the source of these. I used a repro shaft so who knows if that was milled to the right diameter.

When I reviewed the threads about the T-84 leaks there was a lot of banter about a cork seal under the front bearing cap. I found a spare gasket kit from Ron and it had a fiber “seal” in it. So I just left the old one in which was a fiber one. I saw no evidence that oil was coming thru the bearing cap sleeve.

[Wolfman]

Personnel observation on the felt seal that comes in a T-84 gasket set these days.
It is way too thick.
The ones I have seen is 2 felt washers stuck to either side of a center rubber washer.
Put this "as is" into place where the cork seal would normally go and it self destructs. Just too thick to fit in the space.
What I have done is remove the felt from one side of the rubber washer. Install what is left, well oiled, with the rubber side next to the shaft and the felt next to the cover. I have done this successfully.
Or use the cork seal well oiled.

[Carsten]

If you are using a sealed front bearing on your transmission, there wouldn’t be any need for a felt or cork seal on the bearing retainer…

I also had a lot of issues with such a supposedly NOS WOF “wheel” case!


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