Rear diff help

smokin99stroke · May 4, 2013

Sorry for the double post, I posted this in drivetrain forum but figured it would get more exposure here. I really need some opinions today so I can figure out what I need to do because I do need the truck, thanks guys

I'm changing the fluid in the diffs today and take off the rear cover to find this. What is causing this scarring and what should I do about it? The pinion seal is leaking slowly if that makes any difference. Any help would be great. Truck has 212k miles and I'm not sure of the rear diff service history

nwpastroker · May 4, 2013

Drop your rear drive shaft and check the nut holding the pinion yoke on, looks like it could have loosened up and the pinion slid in, or a previous installer may not have properly tightened it and didnt crush the washer

Zmann · May 4, 2013

you better hope that is from a previous episode

I have seen worse but it is definitely from the pinion going to far into the carrier

and since gear lash is so critical if this is a current problem a major failure wouldn't be far behind

smokin99stroke · May 4, 2013

Zmann said:
you better hope that is from a previous episode

I have seen worse but it is definitely from the pinion going to far into the carrier

and since gear lash is so critical if this is a current problem a major failure wouldn't be far behind

I have no way of knowing if this was a previous problem because I've only put 5k miles on the truck and do not know the rear diff history. I suspect it is current because I have a "hum or whine" driving around.

Zmann · May 4, 2013

I would take it in

or investigate on your own but that crush washer and nut spec is like 400 ft lbs

so you might want to have it looked over by an expert

smokin99stroke · May 4, 2013

Can't find anything about 400lb torques, but I certainly don't know where to start as far as backlash and preload and that stuff goes.... Thinking I'll pull the axle and take it in

Zmann · May 4, 2013

I may be wrong on the spec in may be a different procedure
I didn't open the manual and My manual is for a 10.5 sterling I think you might have the 10.25 version

but I would have it looked at if it were mine