M38 T90 Transmission Leak at Counter Shaft

rgmutchler · Post by **rgmutchler** » Sat Jul 28, 2018 4:07 pm

I was preparing to put my body back on the frame but decided to fill the transmission and transfer case with oil without crawling under it. I had the transmission and transfer case "rebuilt" a few years ago. After putting in the oil I noticed that I had oil dripping from between the front of the transmission and rear of the bell housing at the bottom.
I pulled the engine, separated the transmission and after some looking I determined that the oil was seeping from around the counter shaft at the front of the transmission case.
I am disassembling the transmission and might end up with a new case but in reading different posts across the different jeep websites I found that some people say that they put some of the black gasket sealer (not rtv) around the end of the counter shaft just before putting the bell housing back on the transmission. They say the the bell housing up against the front of the counter shaft with the gasket sealant prevents the leaks around the counter shaft.

Wes and all the transmission experts, is this a viable solution to prevent minor seepage.
Thanks

Bobber · Post by **Bobber** » Sat Jul 28, 2018 9:13 pm

I used Ultra Black, Sensor Safe in the same place and ever place I thought it might leak. I have no leaks in either tranny or Trans Case. I was clean with it so it didn't ooze out too much. Good stuff.

4x4M38 · Post by **4x4M38** » Sun Jul 29, 2018 5:27 pm

Ralph,
You have a leak. Putting a sealer between the bell housing and tranny
is just putting a bucket under a leak. It’s not stopping the leak but
postponing the inevitable.

If you have it out I’d look real close at stopping the leak and
fixing it for good.

No fun in 100 degree weather, but that’s what I’d do.

Take care,

MarkR1951M38 · Post by **MarkR1951M38** » Mon Jul 30, 2018 5:53 am

Disregard info below...I re-read the ops trouble again and didn't realize he was talking front of XMSN...my note below was for leak between XMSN and Xfer case

---------------------------------------------------------------

I had a similar leak and I discovered it was the retainer plate that holds the shaft in place...in the oval or cutout area of the transfer case. The plate was positioned incorrectly to prevent exact mating between the transmission and transfer case...it looked good, but leaked like a sieve.

To fix it, I used a piece of manila folder and held it against the cut-out area on the transfer case and used a ball peen hammer to create a template, kind of like you if you made a gasket from scratch. Then used it as a measuring device to see if the plate was seated in the correct area on the transmission....a little to far or not far enough.

Ray101 · Post by **Ray101** » Mon Jul 30, 2018 9:48 am

isn't there a gasket between the bellhousing and transmission? Isn't that supposed to seal the countershaft?

Post by **wesk** » Mon Jul 30, 2018 11:18 am

RG, Are you using the TM's and Rick's T-90 Rebuild guide in the analysis of your leak issue?

http://www.willystech.com/wt/T90Rebuild ... ebuild.htm

I reviewed the final assembly of Rick's guide and there is no mention of sealing the end of that shaft. The shaft is suppose to be a very snug fit in the case. If you have an issue with case hole wear or shaft end wear then I would fix the problem and not apply a bandaid.

4x4M38 · Post by **4x4M38** » Mon Jul 30, 2018 12:19 pm

It’s in Moses Ludel’s book Wes.
Page 208, Jeep CJ Rebuilder’s Manual.

“Apply gasket sealer to the front case bore before
driving countershaft into position.”

Yep, I’ve read all three, including Novak’s guide,
and used the best of all three when rebuilding mine.

Shame there isn’t one all-encompassing, but I guess
I’m grateful we have what we do!

Take care,
Brian

rgmutchler · Post by **rgmutchler** » Mon Jul 30, 2018 12:51 pm

Wes,
As I said in my post, I have a leak around the front end of the counter shaft and that I was probably looking at a new case. Maybe I should have said a new case and/or a new counter shaft.
My question involved" minor seepage" around the end of the shaft that doesn't seem to be unusual. I asked the question in reference to when I rebuild it with either or both of the new parts mentioned above.
Among other places I got the suggestion on the sealant was from Rick's rebuild in the commentary after step 4kk of the assembly steps. It is in his rebuild guide dated Nov. 2005.

Since that time I have a new case and new counter shaft among a lot of other parts to fit together.
Thanks to all that replied.

Post by **wesk** » Mon Jul 30, 2018 3:33 pm

Note that the Ludel reference says apply the sealant inside the counter shaft case hole before inserting the counter shaft and not to the face of the case.

On your gasket question the late M38 bell housing used a gasket between the tranny and bell but it's purpose was for fording operations.

Post by **wesk** » Mon Jul 30, 2018 4:10 pm

Here's the 4KK reference from Rick's guide and Dr Vern actually suggests adding sealant ONLY in the hole at the front of the counter shaft. Not on the flat surface between the tranny and the bell housing. This is more in line with the same approach in Moses Ludel's book.

4kk. Tap shafts into case until the locking plate is held firmly in place. ** See note at bottom of assembly guide

Dr. Vern - The front bore of the countershaft is known for leaking. The end of the shaft is about 1/16" inside the case when fully assembled. I plan to put some sealer in there when I bolt the transmission to the bellhousing. The flat surface of the bellhousing will sandwich the sealer in place. Naturally you don't want to use too much, but just enough to fill that cavity. I'll let you know how it works after I get the jeep back on the road.