pinion seal replacement help

What rearend do you have? Most have crush sleeves and you can't replace the pinion seal without messing up the gear pattern. The 8-3/4 rear with a 742 case has a solid spacer and I think the 741 does also but not sure on that one. If you have one your lucky. Other than the leak which could be caused by a worn spot on the yoke where the seal rides. In that case either the yoke should have been replaced or a speedy sleeve installed.