I have what I believe is a yoke seal leak on a M20 trans in my 69. Everything was put back together with only a couple hundred miles driven since motor, trans, and rear rebuilt. Originally when I had the car inspected they said I had a rear main leak, but I don't see anything in that area. Garage floor was dry for weeks, then a couple quarter sized drops after warming up before driving near the yoke that appears to be gear oil. After driving it dripped another couple dime sized, and now seems to have stopped when not running (no idea when running). Is it possible this seal will swell after some miles are put on and seal itself? And, do you think this is what they were referring to when they thought it was rear main. Seems to be a little off for that, but maybe I have both.

Thanks for the help.

 

Rubber seals have a tendency to dry and shrink a little as they set idle. And there can be a break-in period for the seal to set to the yoke. I would just drive it for a while and see if the leak has stopped for good.

 

Thanks, that is what I am hoping. I am new to the site and have read several of your posts. Much appreciated!