First a little update on my truck. I used to be avid here and then just ran out of time. I browse generally but dont post. Anyways, ive got an 06 4x4 with 130,000 miles on it. Still love the truck and have installed hi/lo HID's (i didnt want to but my son insisted know Ive got fogs on order to match the heads, lol.) I also installed 90w strobes in heads/reverse lights. I looked at trading in for a new one, either 08 2500 or a 09 hemi but couldnt bring myself to keep the same body style with awful interior, or loose the cummins. So it looks like im waiting for the cummins in the new body style.

Pinion Seal:

I got them replaced yesterday because my rear was leaking. I jumped in my truck and headed home never really letting off the pedal. Its about a 20 mile trip to my house. When I exited the highway I let off the gas and as I slowed down I heard a pretty heavy whining that was never there before. I guess the sound of the engine covered it up on the way home. Any ideas on what could have happened to cause my rearend to whine?

 

Sounds to me like all they did was back off the pinion nut, replace the seal and tightened it back down.

More than likely, they either A - incorrectly tigthend the pinion nut back down (either too tight or not tight enough) and now your pinion depth is wrong or B - the pinion bearing was shot from the leaking seal and needs to be replaced as well.

Some folks think that replacing the pinion seal is easy, but to do it right you need to take the diff apart and get everything reset to proper specs.

Otherwise, the pinion depth, pre-load and mesh pattern get screwed up and you get the whining, which if severe enough, leads to diff failure.

 

I doubt it is choice B. As it was just fine before I took it in. It wasnt a major leak, I could just see some oil on the casing. I know the owner of the shop pretty well so im gonna call him this afternoon and see what he says.

 

I would guess they over tightened the pinion nut too.