Brian's 88 4Runner has a good combo of lift, gearing, and protection. The 22RE/5 speed combo has no problem turning 36" Super Swamper SX tires with the 2.28/5.0 dual cases and 571 gear sets.

Recently, Brian busted the rear 571 gearset while up in Moab. Not much history on this 3rd....bought from an on-line forum from someone that said it was originally set up in a Denver 4x4 shop.

These are Genuine brand gears....that's a small part of the issue here. The actual gear install is the main cause of this failure mode.

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Marks to help ID Genuine gears.

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The bearing that seems to always take the worst beating is the small outer pinion bearing. This one seemed ok.

Some minor chinger marks on the cage and one small chip on the race.

Some small dents in a non-critical spot.

2 small shims totaling .020" were found hidden behind the large inner race...typically the shims go behind the pinion head....not the race.

With all the chunks of metal floating around, it's a good idea to inspect the inside of the Detroit SoftLocker.

The spring is fairly strong and it won't knock your face off if it's secured with one hand while the small allen screws are removed.

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The driver and side couplers look great.

The 15 little inside square teeth are all there. I have seen all 15 of those teeth on 2 of my Detroits sheared off in the distant past.

This one is good as well.

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The axle coupler splines both look great.

When compressing the 2 halves together, getting the last 1/2" to mesh is a minor hassle but is doable.

Now to file the surfaces and check for high spots. None found. These are quality 571 Motive gears and they have been professionally cryo treated by Cryogenics International.

Red Loctite and 75 ft/lbs.

Races are pressed in....no shims behind the races.

A few steps skipped here....basically installed the pinion with no crush sleeve...set it for about 10 inch/pounds of rolling drag and loaded up the case with about .008" for backlash. This pattern is much too shallow.

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Even the pinion tooth says the ring tooth is running very shallow.

Teardown and .016" was added to the shim stack.

The pinion seemed to be turning 'rough' and, upon dis-assembly, noticed a new chip in the outer pinion bearing. I wasn't going to take chances with this discovery and substituted in a good used pinion bearing/race I had laying around.

Now it's a little deep.

I will remove .004" now from the pack.

Pinion tooth agrees that the ring is deep as indicated here with a 'shallow' pinion tooth.

Now is a good time to install the solid collar.

The pinion bearings are used so I shoot for 6 inch/pounds.

Aluminum based anti-seize on the threads...

Nice drive pattern....centered and the proper depth.

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Carrier Bearing Pre-Load(CBPL) and BL are tweaked in.

I normally complete the top pinion end before installing the case(Detroit) but it can be done out of order with a solid collar involved.

Loctite and tighten the nut.

Backlash is verified all the way around the ring on every other tooth for a total of 20 measurements. All was good as shown 2 pictures below.

Notes taken on Brian's install.

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ZUK