Had a pinion seal start leaking after a gazillion thousand miles. Replaced that one, and now that one is leaking like crazy after 20,000. What is going on? Things to check?

 

Sounds like the new seal might've gotten damaged from install, or your driveshaft needs to be balanced causing the new seal to fail.

 

Check to see if the surface that the seal rubs against is worn. How quiet is the diff? If there is any play in the beaings, it could cause early seal failure. If the diff is getting hotter than normal because of worn bearings it could cause a leak. It just might be a less than normal quality seal from you know where.

 

Either way, gotta swap it out. Will get a Timken and investigate during the swap. Don’t recall anything suspicious from the last swap.