39 gearbox leak

pooch

pooch

Well-known member
What stops the oil leaking out of the 2 lower shafts that are just a push fit into the case ?

Filled box with nulon SAE 80 , but it went in and out .

Probably chose the wrong oil, but it seems like a lousy design anyway.
 
Clean the area where the cluster shaft and the reverse idler shaft exits the case with acetone then apply J-B weld. Use thicker oil. I stand the transmission case up so the J-B weld will form a thin seal and not run off.
Paul
 
Is the transmission in or out? The last couple I rebuilt , I ground about 1/8 off the end of the shaft then installed an expansion plug sealed with permatex in the case after it was all back together. Another method I've used is to make a plate to cover the end of the shaft plus enough to screw it to the case with a couple of #10 machine screws. But this will involve drilling and tapping a couple holes. They don't have to go all the way through the case though. The case is thick around the shaft hole.
 
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A person can put the shafts in a lathe and cut an o-ring groove but I just apply some RTV to the the receiving bore on one end and to the shaft on side that is last to go in the case. This way they can still be removed but will slow the leak to a minimum. The RTV is flexible enough to allow for temperature related expansion and contraction and a person can still remove them without too much trouble as long as you don't use too much sealer. A person has to make certain that they proceed in such a way as to not fowl any bearing surfaces with the stuff.
 
Thanks all for possible solutions.

Not until I opened the nulon stuff did I see it was like water, too thin.

I did find a post that explained this problem last night.

I was thinking about drill/tap a plate over each shaft, but also thought about drill/tap one hole in centre of shaft/s end and use a single screw to attach a plate and gasket over , it would pull back against the locating pin , will investigate this morning how much meat there is for a screw.

I don't really want to tap the case, but a shaft is expendable.
 
Just make sure your oil is GL1 or GL4 too.

I found that the last shafts I bought only just made spec for diameter.

I use an RTV type sealant when assembling but I still have a small leak..
 
I ground about 1/8" off of the shaft and added RTV and a freeze plug. Same as above. my deal doesn't leak even with RP synthetic.
 
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