8L90/8L90E Overhaul Gasket & Seal Kit with Bonded Piston

When you split a GM 8L90 or 8L90E down for a leak, a valve body job, or to freshen a good used unit, the soft parts are what you never put back in. The lip seals get hard, the sealing rings lose their spring, and the pan and case gaskets never seal the same the second time. This is the KP33900H overhaul kit from Whatever It Takes: the full run of gaskets, O-rings, square-cut and lip seals, metal-clad seals, and Teflon and scarf-cut sealing rings that live in the drums, pump, and valve body, plus the vital small parts, and a duraprene reusable pan gasket so the service after this one is easy.

What sets this kit apart from a plain reseal is the included 1-2-7-8 reverse clutch bonded piston for 2015-up builds. GM revised that piston, and dropping the current bonded version in while you are already inside the unit heads off a repeat teardown for the 1-2-7-8 clutch. It is an overhaul and reseal kit, not a clutch-and-steel master kit, so it is the right box when your frictions and steels still measure good and you are chasing a leak, resealing, or rebuilding a clean core.

This fits the 8L90 and 8L90E eight-speed on 2015 and newer GM rear-drive trucks and cars: Silverado and Sierra 1500, Tahoe, Suburban, Yukon, Escalade, plus the Corvette C7, Camaro SS, and Cadillac CTS-V and CT6. The 8L90 changed detail parts across the years, so confirm your year, make, model, and engine before ordering. Lay it out on a clean bench, work off the exploded view, and replace every seal in the unit in one pass.