Originally Posted by neversatisfied

Is the seal installed dry or with some lube on the lip? Tech told me these seals are teflon and should be installed dry. All previous installed seal I have put in were put in with grease on the lip.

Originally Posted by Bubbubouy

As CRXsi mentioned, I can’t imagine why you would need to replace the yokes unless you have been using the truck for mudding. In that case sometimes dirt will get between the seal and the machined surface on the yoke and polish a groove in the yoke, in which case the new seal may leak immediately or very soon after replacement. Otherwise you can continue to use the yoke.

As for the question of replacing the pinion seal, there are two different methods of setting the pinion bearing preload on any differential of the size and style in your truck. One method is with a crush collar (one time use), and the other is with shims. I have been rebuilding differentials for many years and have only seen crush collars used in small axles such as what would be in the front of a jeep.

Dana 60, 70 and 80 all use shims. I have not yet been inside any of the AAM differentials but I would hope they would use shims.

If you have an axle with the pinion bearing preload established with shims you can just torque the pinion nut to specifications after replacing the pinion seal.

If you have an axle with a crush collar (or you don’t know for sure) use the following procedure.

1) Remove driveshaft
2) With a chisel or cut-off wheel on a small grinder make a line across the nut and the end of the pinion.
3) Remove nut, washer, and yoke
4) Remove pinion seal
5) Install new pinion seal
6) Install yoke
7) Clean threads with brake clean
8) Apply Lock-tight to threads
9) Install washer and nut
10) Tighten nut until your marks line up and you are done

Sorry for being so long winded, this is an easy job but needs to be done correctly. I have seen too many mechanics just use an impact until the nut won’t tighten any more and call it good. This is the difference between an axle that lasts 50,000 miles and 150,000 miles.

Originally Posted by maddog1927

Someone mentioned they felt that synthetics diff oil leaks. Mine happens to be synthetic oil, could there be anything to that? Trying to decide what to put back in.