Oil leak under the M38
 

I recently got a M38A2, we drove it on hard surfaces only and now we have an oil leak coming from somewhere underneath the jeep. We have removed the skid plate and still can't locate the leak. The oil that is leaking is clean/clear, it seems to originate around the transfer case but we can't locate the exact leak point. Could the leak be coming from the driveshaft area?? Transfer case?? Transmission??
The leak is quite big because the puddle gets quite big. The jeep has not moved recently because it is on jack stands. Can someone tell me where to look. If you know M38s and have some free time on a Saturday I would gladly pay expenses etc to help locate the problem.
I really get frustrated when I can't find leaks and my patience levels diminishes every time I walk by the jeep.. I have 7 other trucks ranging from CUCVs to 5 tons and none of them leak but this damn jeep does. HELP PLEASE. Gilles

Rear seal
 

Look at the rear seal on the transfer case. The output shaft connection
and all hand brake components have to be removed but it's not a big deal. Drain the transfer first. And make sure you have two new seals standing by.

Simundson

First off, does the oil have the distinctive smell of hypoid, or is it engine oil? The rear engine seals on the Willys were not really what you would call perfect. Same goes for the front transmission seal, it was a felt washer, and not a true seal.

There are only so many places a jeep can leak from the transmission/t-case. Spray the whole area down with engine shampoo and then pressure wash everything down there. After a quick run, the source of the leak should become obvious.

I have a JP Magazine article on how to rebuild the T90 transfer case, and if you go on line there are a couple of thorough step by step websites.

There is a weeping hole on the bottom of the bell housing that reacts to high oil pressure(?). I remember having to lay the drip pan under one of our militia M38A1s after an exercise because of exactly what you describe. I thought we'd blown something until the mechanic sauntered over and did a few checks, shrugged his shoulders and said no problem with this one. Back to something more important.

That hole on the bottom of the bellhousing lets out the seepage from the engine rear seal, and also lets out any seepage from the transmission front seal. Any excess leakage into there can oil soak the clutch causing it to slip. That little hole is also the one referred to on the dash "bellhousing decal where is says to "install bellhousing plug before fording/remove after fording".

I saw a deuce once where the operators had so much oil leaking from there (thinking that the plug had fallen out), they called recovery. When recovery took too long, they whittled a plug out of wood and drove her home. Monday morning I removed the stick and let all the accumulated engine oil drain from the bellhousing. Of course, the engine had developed a knock from lack of oil and had to be replaced now.

Oil?
 

What's been over-filled?

Deuce had an automatic tranni...

f

Yep, but it still had a drain hole on the bell housing. In this case it was the engine that leaked and not the transmission.

Following the posts and having my Friend Dave from Windsor look at the vehicle we found that the transfer case outseal seal was the leaker. We also found the the seal on the rear diff had been sealed with silicone. We ordered the parts and they should arrive next week.
We also ordered new parking brakes and paint to redo the vehicle. It should be an interesting project.

Gilles