...could be overfilled, incorrect ID of seal from supplier, different OD of sealing surface on yoke......and YES, I use the hammer method.

 

To anyone with a pinion seal or axle seal leak, front axle or rear axle, make sure that your breather vent for that differential is working. Check that the vent is free to turn, also that the hose extending the breather vent up into the frame rail or box cross member is not kinked or has broken off and the lower part of the hose plugged with dirt. If any of these things happen then the differential will build up pressure and force your gear oil out at the seals.

Cooter

 

Don't top them off. When I got my 03 I topped it off only to have it leak later. After the dealer replaced it twice, I serviced them with Amsoil and made sure they were filled correctly. No leaks 63k.