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I mentioned the following in a prior post, but it was at the end of a write-up for pinion seal replacement so I thought I'd do a shorter post about it here.
I recently replaced my front differential pinion seal and it stopped the leak. The problem is my preload is too high -- 40 in-lbs to turn it. It's supposed to be in the neighborhood of 5.2 - 8.7. I got the pinion nut back on to the position it was before I took it off, and it felt like it took the same amount of force to turn after as it did before. Ergo, it seems it's been this way for some time. The torque needed to get it to where it was before was just over 90 ft-lbs. The minimum torque spec is 89, which can be increased to around 150 if needed to get more preload. I have too much, however, not too little.
The manual says if this happens to replace the bearing spacer. Problem is this requires removing the bearing, which requires a special, hard to find and expensive tool (SST 09556 - 22010). I doubt my mechanic has this tool either, so he'd probably need to take the diff off, at which point a full rebuild starts to make more sense. I'm also not sure the bearing spacer is the entire problem or if I also have bad bearings. If the preload has been this high for a long time, it seems likely they would be on their way to failure.
Anyone have insight, advice, tips, or life experience to lend for this situation?
If someone by chance had the SST 09556 - 22010 specialty tool, maybe we could work out a way I could borrow it with a deposit and a premium?
Lastly, assuming I got the outer bearing out, I'm guessing replacing it but not the other bearings would be a bad move? I'd assume the inner bearing and all the races would need to be replaced as well, and basically the whole thing rebuilt.
I was preparing to replace the seals on both the front and rear diffs. I've got the seals, bearings, crush sleeves coming from amayama.
once i get the bearings I'll start looking for a puller that can grab the lip on the inner race. I don't expect my parts to arrive for another week or two, though.
I cringe when i think about all the old OTC tools I disposed of to make room for the new ones.
It is not possible to determine pinion bearing preload when the pinion is dragging the whole differential and axles with it when you act on it.
Naturally, the force needed to move the complete gear-train is going to be substantially greater than pinion preload alone.
Actual preload might only be measured when nothing but the lightly lubricated pinion itself is the only component being turned.
There is probably nothing wrong with your gear case.
I'll never be more happy to be wrong, but I did get my information from the FSM and it says 'On Vehicle Repair' (see pdf attachment). Am I missing something?
"""Using a torque wrench, measure the preload of the backlash between the drive pinion and ring gear.....""""" Backlash, BACKLASH.
Backlash is the couple degrees of pinion flange travel where the pinion is actually free of contact with the ring gear. Usually 6 rr 8 thousanths of an inch, measured with a dial indicator at the outside of the ring gear tooth perimeter.
Good luck getting a reading of only pinion preload in between this small swing on your assembly. If you can actually feel this fine line, it's gonna be lots less than your whole gear train measurement.
Like I said, probably nothing wrong with your gear case. If there was, It'd have likely already failed.
"""Using a torque wrench, measure the preload of the backlash between the drive pinion and ring gear.....""""" Backlash, BACKLASH.
Backlash is the couple degrees of pinion flange travel where the pinion is actually free of contact with the ring gear. Usually 6 rr 8 thousanths of an inch, measured with a dial indicator at the outside of the ring gear tooth perimeter.
Good luck getting a reading of only pinion preload in between this small swing on your assembly. If you can actually feel this fine line, it's gonna be lots less than your whole gear train measurement.
Like I said, probably nothing wrong with your gear case. If there was, It'd have likely already failed.
Got it. I've never been so happy to look like a dumbass. What a relief. Thank you sir.
90 foot pounds is the absolute minimum you should tighten the pinion nut to. You should go ahead and take it up to 130 for security. 130 is not nearly enough to compress the crush sleeve any.
90 foot pounds is the absolute minimum you should tighten the pinion nut to. You should go ahead and take it up to 130 for security. 130 is not nearly enough to compress the crush sleeve any.
I was just wondering if I should do this, but wasn't sure how much tighter so thank you. Makes sense to tighten a bit due to bearing wear like you said 90 being the minimum. My mechanic mentioned tightening it something like 180, but I feel more comfortable with 130.
Here's what the nut looked like after torquing it to 130. You can see how far it moved it from where it was:
Then after re-staking. Not the prettiest job, and might be the last for this particular nut. But should do the job. I've seen on the internet specialty tools by Schley for staking and unstaking, but I made do with a chisel and punches:
I know, the pictures are big. I'd resize if it were easier on here.
09-22-2020, 12:11 AM
