I replaced the slip yoke and u-joint on the TH350 (with one that doesn't have the weep hole - which inevitably leaks). While I had the tail housing off, I replaced the bushing and rear seal as well. What type lube should be applied to the outer surface of the slip yoke and to the output shaft/yoke splines before re-assembly? Thanks.

 

I just use a very light coat of grease.

 

+2

 

Thanks again.

 

Trans fluid is the only lube to use in and around an automatic. Grease can wick in from the tail shaft and contaminate the trans fluid. The frictions, steels and seals don't like grease. Petroleum jelly can be used to hold check ***** and seal springs in place but that's the only other petroleum product an automatic trans should see.

 

^^^This.

The reality is that as soon as you start driving, ATF splashes around inside the trans and lubricates that seal anyway. A light film of ATF at installation prevents a dry startup.

 

I remember using petroleum jelly back in the day on the slip yoke/rear seal. I'll use only A/T fluid now rather than risk contamination. Thank you for the follow-on replies.