4L60E Rebuild Kit with Bonded Piston and 3-4 Clutch Pack

This is a full soft-parts-plus-clutches overhaul kit for the GM 4L60E and 4L65E four-speed automatic, 1997 through 2003. It covers the whole rebuild in one box: paper and rubber gaskets, lip seals, O-rings and sealing rings, the friction plate set, the steel plate set, the front band, the deep-pan filter and pan gasket, and the bonded 3-4 clutch apply piston.

The bonded piston is the part worth paying attention to. The original 3-4 piston on these units uses a separate bonded lip that hardens and cracks with heat and age, and once it leaks the 3-4 pack loses apply pressure, slips, and burns. That is the single most common failure on a high-mileage 4L60E behind a 5.3 or a 4.8 - the truck goes into fourth, then flares and starts glazing the pack. Rebuilding with a fresh bonded piston and a new 3-4 clutch set is what keeps the repair from coming back.

Fitment covers Chevrolet Astro, Blazer, Express 1500, S10, Silverado 1500, Suburban 1500, Tahoe, Trailblazer and Trailblazer EXT, Camaro and C1500; GMC C1500, Envoy and Envoy XL, Jimmy, Safari, Savana 1500, Sierra 1500, Sonoma and C1500 Suburban; Pontiac Firebird 1997-2002; and Cadillac Escalade 1999-2003, Escalade EXT 2002-2003 and Escalade ESV 2003.

On the bench: strip the case and air-check every circuit before you start putting parts in. Replace every lip seal and Teflon ring, not just the ones that looked bad. Soak the new frictions in Dexron VI for 20 minutes minimum so they are saturated before the drums go together, and set clutch pack clearance with the right selective before you close anything up. Inspect the reaction sun shell and the pump slide while the unit is apart - neither is in this kit, and both are common enough on these years that you do not want to find out after the pan is back on.