Rear transmission leak

[Chris]

Hey guys, I have a 1939 Ford three speed that I put in my 34 Ford. I went through it myself and it shifts excellent. It is leaking out of the back, seems like under where the rear trans mount bolts up to the case. I pulled the mount off, could not pin-point the leak but used some sealer around the two shafts and put it back together. It is still leaking...pretty good leak (leaves a small puddle after a couple days). With the trans saddle I cannot see directly up to the back of the trans to see the leak, but it runs down the back of the case, then down the bottom and drips off the drain plug onto the ground. Is there anything else back there that could be leaking? It is definitely gear oil and not grease or anything. The mount, and under the mount, are bone dry. I'm guessing it's the shafts...any other thoughts?

Thanks guys.

[Kube]

Did you seal around the pin that holds the shafts in place?

[Chris]

Originally Posted by Kube

Did you seal around the pin that holds the shafts in place?

Hmmm....no, good idea! Too bad I gotta pull it all back apart to get to see that

[FlatheadTed]

If the gasket is not in good shape at the bell you get splash over ito the U joint cavity ,then it runs down ,or on the mount side .

[Hoop]

Chris, you do not mention what grade oil you are using in your transmission.

If it is 80/90 or something in that range, you might consider draining that out and replacing it with STRAIGHT 140. Try O'Reilly's. They usually carry a good GL4/140 ... otherwise it can be hard to find.

Do not overfill. I use it in my transmissions (with "39" gears) and it makes a huge difference not only in stopping/slowing leaks, but also in the synchros. Some oils are simply too slippery.

(Any mention of oil always sparks a big discussion involving how many "oil angels" can dance on the head of a pin. GL4/140 is near perfect for your gears unless the temps drop below freezing which might slow it down until it warms up.)

[expavr]

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I agree with Hoop about overfilling and would add that I use a 50-50 blend of NAPA GL 1 90 wt. and Lucas HD Oil Stabilizer (http://www.lucasoil.com/products/dis...l%20Stabilizer) to deal with a leak a countershaft leak in my 49 Merc O/D trans. So far its been effective. Instead of a leak it now weeps slightly.

[Dick Webber]

I ran into that problem with my 49 F-1. I had used a new replacement non Ford countershaft shaft which was a bit undersized (and also very soft). I installed a new shaft, sealed the ends with permatex and fixed the problem.

Dick

[Russ/40]

Originally Posted by Chris

Is there anything else back there that could be leaking? It is definitely gear oil and not grease or anything. The mount, and under the mount, are bone dry. I'm guessing it's the shafts...any other thoughts?

Thanks guys.

Yes, the hole that is perpendicular to the shaft for the locking pin is probably leaking.