transmission fluid leak

[Lt.Del]

I got one for you master mechanics.
I walked around my 79 Big 10 today.  I haven't driven it for a few days and I noticed a puddle of tranny fluid coming from under the truck.



So i crawled up under it and at first thought it was the donut-type seal for the slip yoke.  But, it was dry all around that seal.
I looked closer at the drips--it is still dripping as I type this, and it seems to come from the yoke itself.. 



Isn't there a hole that goes through the center of the yoke itself?  What could be wrong?  It drips directly from the u-joints....the yoke around the seal is dry so it couldn't be a bad seal there.   

[VileZambonie]

there is a bulletin on those leaks. I used to just plug them but I'll see if I can dig it up for you

[Captkaos]

First thought is this:
http://www.73-87.com/7387garage/drivetrain/yokeleak.htm

[Lt.Del]

I don't remember that "cup" being there when I put my trans in the truck and slid the speedo gear on the tail shaft, maybe I just have alzheimer's, but I don't remember that being on my TH350c. 

Vile, if you plug the weep hole, what do you plug it with?

thanks for the help, as always.

[VileZambonie]

Jb weld works fine or if you don't have any clean it out and put in some good RTV

[ccz145a]

I packed some white lithium grease back in there.

[Lt.Del]

Thanks.  As soon as I get back from the Outer Banks of NC, I'll drop the drive shaft and tail cone of tranny and investigate the o ring.  If I can't see that, I'll just plug the weep hole up.

thanks for the input.
   

[Lt.Del]

Well, I removed the driveshaft today.  Removed the tranny extension housing and speedo cable.  Saw the cup with the O ring.  Went to the salvage yard and removed a cup from an existing th350 and put it on my trans.  So far, no problems.