GM NP246 Transfer Case Rebuild Bearing & Seal Kit BK-351

This is the bearing, seal, and gasket kit you need to rebuild a GM NP246 (New Process 246) transfer case, the electronic AutoTrac unit bolted behind the 4L60E and 4L80E in 1998-2007 GM full-size trucks and SUVs. It fits the Chevy Silverado 1500, Tahoe, Suburban, and Avalanche, the GMC Sierra, Yukon, and Yukon XL, and the Cadillac Escalade. Part number BK-351 / BK351.

The NP246 has one classic failure: pump rub. The internal oil pump slowly wears into the aluminum rear case half until it opens pinholes, and the case starts bleeding fluid. By the time you catch it the bearings are usually dry and howling. Whenever you are already inside the case for a pump-rub repair, saver plate, or a noisy input, you replace every bearing and seal at the same time so the job only comes apart once.

The kit carries all of the internal bearings, the front input and rear output shaft seals, the transfer-case-to-transmission adapter gasket, and a full set of new O-rings. On the bench you press the old bearings and races out, drive the new ones in, set the new seals, and reseal the case halves with the fresh gasket and O-rings before torquing it back together.

Bearings are high-strength steel. This is a rebuild component set, not a complete case, so pair it with a chain, pump saver plate, or clutch pack as your teardown calls for.