T-90A-1 Transmission Leak

dv3468 · Post by **dv3468** » Fri May 04, 2007 9:25 pm

Gentlemen: I started driving my recently restored M-38 and notice that I have some transmission fluid leaking from the weep hole on the bottom of the bell housing. It's not a serious leak, but I am kind of surprised since I replaced the main oil seal on the front output shaft. I get a 2-1/2 inch oil spot on a piece of newspaper I put under the tranny after I shut off the engine. The spot takes about two hours to form, then the leaks slows to about a penny sized spot after several days, then stops completely after four plus days. I have about ten hours running time on the engine/transmission since I restored the jeep. Is there an anti-leak additive I can use in manual transmissions similar to the ones made for auto-transmission seals? I hear that the T-90 transmissions are notorious bleeders! Thanks in advance for the advice. Regards to all, Dennis.

Nekaffan · Post by **Nekaffan** » Sat May 05, 2007 2:14 pm

I've got the same problem with my m38a1 Nekaf and most of the people I know with a m38a1 too. The problem is that when you don't drive your jeep, the oil of your transmission is cold and when you drive it, it gets hotter, as a result of that thinner and starts leaking a bit. I don't know if there is an additive for it, if anyone knows there is, i'm interested. In my opinion it is easier to check the levels of the transmission oil from time to time and fill it up if needed, rather than changing the oilseal again with probably the same result as before.

cmpman · Post by **cmpman** » Sat May 05, 2007 2:28 pm

The felt seal on the imput shaft is hardly what you could call a positive seal. If you are real finicky about it, with a bit of modification, you can install a normal seal into the bearing retainer. I did this once before and had good results.

dv3468 · Post by **dv3468** » Sat May 05, 2007 5:52 pm

Gentlemen: Thanks for the response. I had the jeep out today since it was beautiful here in New Jersey. Everyone was out driving their toys around town today! I also noticed that the tranny was leaking more then usual since it was 74 degrees today. I wonder if you put a heavier weight fluid in the tranny during warm weather would have any affect on the leaking?

Regards, Dennis

Post by **wesk** » Sat May 05, 2007 10:19 pm

You could try the multi-weight 90/124 gear oil. But in the end you will have to provide a better seal for the input shaft.

Try this site for the how too:
http://www.willystech.com/wt/T90Rebuild ... ebuild.htm

RickC · Post by **RickC** » Sun May 06, 2007 9:23 am

I was just going to post the same thing about my M38. Doesn't leak while running it but when I shut it off it leaves a puddle then stops leaking completely. Didn't do it much at all when I first started driving it but did it first 2 times this year. Hate pulling the tranny to replace seal considering there were all new seals put in recently. Glad to know I'm not the only one with this issue.
Rick C

dv3468 · Post by **dv3468** » Sun May 06, 2007 10:56 am

Rick: I guess we made eachother's day! I pulled that tranny out four times during the restoration. Fortunately, I didn't have a body to get in the way. If I have to take it out again with the body on the chassis, I'll shoot myself!!!

I'll just make sure I have enough pee-pee pads for the old girl!!!

Regards, Dennis.

TOM-R · Post by **TOM-R** » Mon May 07, 2007 6:59 am

are you sure the rear main seal on your engine is not also leaking some? it would also drip from the bell housing

dv3468 · Post by **dv3468** » Mon May 07, 2007 11:22 am

Thanks for the thought Tom. But it is definitely transmission fluid. I can tell by the sulfur smell and the color. Dennis

Post by **wesk** » Mon May 07, 2007 11:24 am

Tom brings up a good point. There are three sources for an oil leak from the bell.
1-Fronty tranny seal which smells like gear oil.

2-Rear main bearing cap seal smells like engine oil.

3-Cam rear bearing welsh plug smells like engine oil.

Item 3 is hard to see with flyheel installed and many times folks will do several rear main reseals before locating the real leak further up.

usma41 · Post by **usma41** » Thu May 10, 2007 9:42 am

They all leak! get use to it.

dv3468 · Post by **dv3468** » Thu May 10, 2007 11:26 am

That's all I wanted to know my good man!!!

RickC · Post by **RickC** » Thu May 10, 2007 5:51 pm

I took mine for a 20 mile ride last night and went to a cruise night. Couldn't get it to leak a drop. It dripped a bit after it was in teh garage though. Maybe just marking its territory??????
Rick C

dv3468 · Post by **dv3468** » Fri May 11, 2007 7:38 am

Rick: I'll send you some pee-pee pads!!!