Complete bearing, seal, crush sleeve, shim and hardware kit for installing a new ring and pinion in a GM 218 mm (8.6 inch) 10-bolt rear axle.
Ratech kit 381K is a complete installation kit for the GM 218 mm ring gear axle, the 10-bolt rear that GM calls the 8.6 inch. It covers a full gear swap or a bearing-and-seal overhaul in one box: carrier and pinion bearings, a new crush sleeve, pinion seal, cover gasket, setup shims, ring gear hardware and marking compound.
On the bench, pull the carrier and pinion, press off the old bearings and use the shims in the kit to set pinion depth against the new gear set. Install the new crush sleeve, torque the pinion nut in small steps until you reach rotating preload, then set carrier preload and backlash with the side shims. Paint the ring gear with the marking compound and read the pattern before you button it up. Do not reuse the old crush sleeve; once it has been crushed it will not hold preload.
Worth doing whenever the 8.6 starts to whine on decel or under load, when a carrier bearing has gone rough, or any time you change ratio. The seals and gasket in the kit mean the axle leaves the bench with no old rubber left in it. Confirm your axle by the ring gear size (218 mm / 8.6 in.) and the 10-bolt cover before ordering; the older 8.5 inch 10-bolt uses different bearings.
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Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
