[ralphnof49]

I have replaced the rear seal on the overdrive without removing the transmission from the car. Now I need to put everything back together when the gaskets arrive. My question now is what grease should be used- the service manual says "cylinder oil soda soap grease". I can find reference to the various compositions of grease on the internet, but it doesn't help with the specific product to use and the U joint needs to have grease that will flow into the bearings readily. What should be used?

[peecher]

The cylinder oil soda soap grease was a "duke's mixture" that had a fairly low drop point and would "melt". This would prevent "tunneling" of the lubricant as the u-joint spun. You can use the lowest drop point chassis lube available ( usually the cheapest) or a mixture of chassis grease and gear oil.
Glad to hear you were able to change that seal without removing the transmission.

[ralphnof49]

Thanks for your help Peecher.

[CBoz]

Here's some info from Dick Spadoro, via the Fordbarn. Pretty useul:

Re: 1939 Ford transmission

In fact, I just got done putting the 600 wt oil into my u-joint assembly. I had the tranny cover off, so I could see how it created an "oil bath" for the speedo cable and driveshaft roller bearing as well. And so far, no leaks (the stuff is like molasses and the cork/felt seal at the back of the u-joint cover may be enough to hold it in).

[ralphnof49]

Thanks CBoz, I have never seen 600 wt oil. I will have to look around for heavier oil than regular gear oil.