GM 6T30/6T30E Master Rebuild Kit Chevy Cruze Sonic Encore

This is the master overhaul kit for the GM 6T30 and 6T30E, the small transverse six-speed automatic from the front-wheel-drive 6T family. It sits behind the 1.4L, 1.6L and 1.8L engines in cars like the Chevrolet Cruze, Sonic, Aveo and Trax and the Buick Encore and Verano, and it is the lighter-duty sibling of the 6T40 and 6T45. When one of these units starts flaring on the 1-2 or 3-4 shift, slipping under throttle, or drops fluid that comes out dark and burnt, the clutch packs and seals are worn and the transmission needs to come apart.

The kit carries the wear parts you replace on a full teardown: 14 friction plates and 14 steel plates for the clutch packs, plus the gaskets, lip seals, sealing rings and o-rings that go back in during reassembly. It covers part numbers B210820A, B210880A and W210881A. The frictions are cut to hold line pressure without chatter and the steels are ground flat so the packs clamp evenly and release clean.

On the bench you use it after the case is split and the channel plate, pump and drums are out: soak the new frictions in ATF, reclutch each pack to the correct plate count and clearance, reseal the pistons and drums, and refit the pump and valve-body gaskets as the unit goes back together. It is the parts side of a rebuild and does not include the torque converter, valve body, hard parts or the friction wave plate, so inspect those separately and add what your teardown shows.