Has anyone changed out their rear pinion seal? Does it involve removing the pinion gear itself or just popping out the old seal and installing a new one?...topping up for lost oil of course, or am I going to need to replace all the Royal Purple I just put in a month ago?

Thanx for your help...

 

Yes you can change just the seal with one exception. The 10.25 diff has a crush sleve behind the front pinion bearing a common mistake is to install a new seal then just slap the yoke back on and tighten the nut. if you are lucky you can do this and still have correct preload but it is unlikely. You need to pull yoke off remove seal. then remove the pinion bearing this is the tricky part some will slide off easily other not so easy. after you get the bearing out you can pull out the old crush sleeve. reinstall in same order with new crush sleeve. youll notive th new sleeve is taller. when you tighten the nut it will get tight but have to continue to tighten to set preload on bearing . It takes a lot off force to crush the sleeve. i recommend a 3/4 drive impact or 4 foot ratchet be careful when getting close and check with inch pound torque wrench till reach correct preload.. you'll need a split beam type wrench..The spec 12-16 inchpounds on used bearings. however check it before you take it apart. You will have to pull drive axles to get accurate reading. inspect the pinion bearing closely . I had a failure in front pinion bearing. but you'd hear a noise if was going out.any way thats the bulk of it. good luck.

 

Thanx for the info... I know the dealership quoted 1.25 hours labour and said it would need topped up with fluid that leaks out. Didn't want to trust what the dealership said. Will make sure the crush sleeve gets replaced.

 

Ummm... replacing that crush sleeve affects pinion depth. If you slam that sleeve down too much, you're going to get a nice hum from your rear end, and put abnormal heat and wear into the scenario. I would measure the pinion depth with a dial gauge attached to the housing, and be sure to put it back exactly where it was.

 

I was talking to my local indy mechanic and he warned of the same thing... will probably try just replacing the seal for now.

Thanx for the advice though.... muchos appreciated.

 

The pinion depth is set with shims behind the rear pinion bearing. the spacing from there to the race in housing will not change. the crush sleeve is between the front bearing and seats on the pinion shaft. This is to adjust the bearing preload.the pinion depth would be affected by the amount of preload that you apply to the bearings but it would be such small amount that the gear pattern would not change. it takes about .003 inch to make a noticeable change on pinion depth pattern. I would replace only the seal to start with if I was you. just be sure to check that when the nut is tight you still have proper bearing preload. If you check the preload and it is to tight but you do not have adequate torque on the nut then you will have to replace the crush sleeve. Hope this is helpful.

 

How do you determine the preload on the pinion? Is that the amount of torque it takes to move the gears? Is the torque on the nut and the pinion preload the same? I'm trying to figure this out all in my head before I start taking it apart, thanks!

 

I believe i recall the preload is 14 inch pounds. that would be the forc it takes to turn the pinion shaft. with no load from th drive axles or carrier. I,ll tell you the easiest way for me. you need to remove your drive axles to get a good feel. and then when tightening nut check it with small amounts of turn when you get to zero play. cause if you hit zero lash and then say go another turn. it might be to much. but anyway if you twist the pinion with you han like you would tightening a swcrewdriver. whenyou have a good firm resistance. to move the pinion thats about right. or buy a 1/4 drive split beam torque wrench and check it. maybe this will help.