Pinion Nut Torque vs Bearing Preload Torque???

I've read alot of posts about the proper amount to tighten a rear pinion nut. I got all the torque specs n stuff from all that so I'm not asking for that.

I'm confused about ONE part that I think I understand but I'm not positive that I'm correct. I just need clarification. Most posts say tighten the PINION NUT to about 150-300 lbs of torque but THEN they say the BEARING PRELOAD should be 15-35 lbs of torque.

What is the difference here? 150-350 lbs is alot different from 15-35 lbs. I'm PRETTY SURE the 15-35 is how much torque should be required to rotate the entire pinion assembly and NOT what the nut needs to be tightened to but I'm not 100% sure.

If thats the case I'm driving around w/ a very loose pinion nut but if thats not the case I'm afraid I'm going to destroy the crush sleeve and create far more work for myself than I'm looking for.

I don't care if its tightened perfectly I just beleive it needs to be alot tighter than I have it and I'm trying to figure that out.

For reference...this all came about when I needed to replace the oil seal. It is still leaking oil tho. Also the DS doesnt vibrate or whine while I'm driving (from what I can hear/feel) but if I crawl underneath and physically shake it it does rock back n forth a little bit. This stuff is whats making me beleive its loose. Or maybe its something more?!

FEAR...

anyways...help...suggestions?

ALSO...for reference...stock 1990 XJ w/ a D35

The 150-350 FT lbs is the torque of the pinion nut itself.

The 15-35 IN lbs is the torque required to begin rotating the pinion (Assuming that number is correct? Sounds right to me...)

Question answered Looks like I gotta go home and tighten this nut...thnx!

Yeah but it's not that simple if there's a crush sleeve in your diff.

As you can see that spec of 150 to 300 ft lbs is a huge range.

Tell us more about why you had the nut off. Was it to replace a leaking seal?

When you are retightening a pinion nut onto a pinion that the crush sleeve is used and already crushed, you basically have to strive to get the nut back to the same position it was in before. That may take 75 lbs of torque, or it may take more. The easiest way to do that is to mark the nut and pinion shaft with a chisel before you take the nut off, replace the seal or whatever you have to do, and then tighten the nut back to the same position.

If you didn't mark the nut, the next best thing is to tighten the nut until the rotational force required to rotate the pinion is in the range of 14 to 19 inch lbs.

But that spec is only accurate with the carrier removed, and that's alot of work and a new can of worms in itself.


If you're not going to do any of that, and just want to tighten the nut and hope it's o/k. I could only suggest that you tighten it to about 100 ft lbs torque, then also I would use locktite and try and use a sharp chiesl to stake the nut, so it has a better chance of not moving on you.

Hope that helps!!