Drivetrain 8.8 rear gear change


Active Member
Sep 25, 2019
Good morning,

I will be changing the rear gears in my 87 to 3.55s in the near future.

I will be doing the work myself.
I have not done this work before but have a mechanical background and am confident I can get it set up correctly.

My question is, is it necessary to replace all of the bearings when I do the gear change? My car has 60k original miles and the rear is quiet, no leaks except the pinion seal, which will be replaced and I'll sleeve the flange if its grooved.

Will I be able to press off and on the pinion bearing without damaging it? I do have a 20 ton shop press.

I would think using the frpp gears and reusing the existing bearings and shims that possibly no adjustments will be necessary, of course I'll check, I have a dial indicator to check backlash, just have to buy a magnetic mount for it. I do need to buy a beam style torque wrench and pinion holder (or make one) to check pinion preload and to crush the crush sleeve when tightening the pinion nut.

My car sees 500 miles per year tops and the rear is in good shape/quiet.

So, I figure no need to spend extra money and may make it easier to set up or possibly no shim adjustments necessary if I keep everything as is and just change the ring and pinion.

Any helps thoughts or suggestions would be appreciated.

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Most of the time you can get away with using the old gears and shims with quality frpp gears. Usually, the bearing wears causing the seal leak. The slight movement will make the seal leak....just like axles and axle seals. There's a 50/50 chance that the bearing will come off without damage. You'll need a bearing separator plate

This is where it gets complicated. The new replacement gears can be different than the original. I've seen where the bearing taper was slightly different so if you change the bearing pop the race out too. ( I'm sure you would anyways ).

Before removing the pinion nut you can check pinion depth and make sure the new one is set to where the old one was. A bunch of people are terrified of rear gear swaps. Just take your time and it'll be really simple. The hardest part is crushing the crush washer.
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Make yourself a pinion set-up bearing. Cheap and easy to do, and well worth the time/money when setting up your lash.

If you do, get the same brand and same part number bearing as the one you're going to use for final assembly.
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