Jadoun

Hi, Anyone can tell me who difficult to replace the pinion seal, as my truck leaks oil from the rear differential and I added around 3/4 liter of w90 oil. I know the oil that should be used is 75w140 but I stopped at one of the oil shops and found only this type of oil! Not sure if this will case any future problems?
Pls help!

Bubba Sides

It's not that hard if you are mechanically able. There are ment dig threads on this. Just be very cautious and do it right the first time or you'll open a can of hurt when you have to rebuild the entire rear diff. As far as the fluid goes. I turn wrenches on BMW's all day in and out and am a try believer that you only put the exact fluid in anything but it's your truck . Good luck

sdmartin65

80/90 gear oil is non synthetic where 75/140 is synthetic, won't hurt a thing. Remove pinion nut and change the seal. The nut will stop at the crush sleeve when reinstalling. It takes a lot of torque to crush the sleeve down further so it it's installed tight it will be fine. Use thread lock.

Jadoun

Thanks so much for the valuable answers

jamie930

I dont know about the 9.75 but on the 8.8 the pinion nut is a one time use and the depth is set by shims not a crush sleeve

Bubba Sides

The pinion death is also set on the 9.75 with the use of shims. But the pinion bearing preload is set with a crush sleeve. This is very crucial and from my experience just a quarter turn past where the nut was and your preload won't be in spec.

sdmartin65

This is correct but it takes a lot of torque to crush that sleeve and move the quarter turn. Can't be done with an 8" ratchet.

Dsherman

I did mine last year and got the parts from Ford. Wasn't very much and marked the nut and pinion and counted the required turns to remove the nut. I does take quite a bit of force to break the nut loose. Probably helped that I did it on a lift. I know cheating right. There was a write up here or on another forum that I used, with pictures. I think I posted about it here when I did it.

redeye3745

No it's not hard, I was less mechanically inclined when I changed mine. Deffinitely drain it first. Get a gear puller from O'reily's. I was able to use a cheater bar to break the nut loose. Mark it first. And put some loctite on the nut when you put it back on. One thing that will help is count the threads on the bolt before taking off. Mine had 7. And you can't really add too much diff oil, as long as the vent tube isn't clogged than you'll be good

Jadoun

Finally I did it .. It was good experience. Also I changed the diff oil with Valvoline 85 w140 it's not synthetic but I heard that it's good oil?!!
Thanks all for your help I really appreciate all given information about this issue.