Master rebuild kit for the GM 6T40E and 6T45E six-speed used in the Chevy Cruze, Buick Regal and LaCrosse with 1.4T, 1.8L, 2.0T and 2.4L engines.
If your 2011 Chevrolet Cruze, Buick Regal CXL or Buick LaCrosse has lost reverse, flares into 3rd or 5th, slips in several gears or is throwing P0776, the 6T40E or 6T45E under the hood is probably ready for a full overhaul. This master rebuild kit (part number DAY-D-6T40E) is listed for the 2011 Cruze with the 1.4L turbo or 1.8L, the 2011 Regal CXL with the 2.0L turbo or 2.4L, and the 2011 LaCrosse CX/CXL 2.4L, so the whole unit can be resealed and the clutch packs renewed in one teardown instead of ordering seals and frictions a piece at a time.
The 6T40E and 6T45E are GM's transverse six-speeds, built around five clutches that are applied by bonded pistons and controlled by the TEHCM, the combined TCM and solenoid body bolted inside the case. Every 2011 unit is a first-generation design: the 4-5-6 drum runs four sealing rings, four frictions and a wave plate, and the TEHCM still carries the fluid pressure switches GM dropped for 2012. A master kit supplies the frictions, steels, seals and gaskets that wear in that layout, so after the rebuild every circuit holds pressure again and every clutch starts from fresh material.
A 2011 build sits right on top of the 6T40's best-known failure. GM Preliminary Information PI0780A covers 2008-2011 units built on or before Julian date 11-015 (January 15, 2011) with no reverse, no 3rd and P0776, and names the broken 3-5-R waved plate as the cause. Pull the pan and look at the magnet: steel debris settles the question. Before condemning the unit, rule out an overfill and a software issue, and do not replace the TEHCM first. GM's PI0670A says to inspect the 3-5-R clutch and piston before swapping the TEHCM on a Gen 1 unit. Our 6T40 common problems and fixes guide lays out the order, and the 6T40 rebuild cost breakdown shows which teardown findings add to the bill.
This kit is listed for the 2011 Chevrolet Cruze 1.4L turbo and 1.8L, 2011 Buick Regal CXL 2.0L turbo and 2.4L, and 2011 Buick LaCrosse CX/CXL 2.4L. Those engines are split between the 6T40E and 6T45E, which share the same basic architecture, and GM made running changes inside the 2011 model year, including dropping the notched 3-5-R piston. Compare the clutch stack and drum that come out of your case with the kit before you start, or send us your year and VIN and we will check it. If your car is a 2012 or later, start with the 2012 6T40 master rebuild kit or browse every option on the rebuild kit category page.
Split the case and clean every passage: PI0780A warns that skipping the full disassembly and cleaning after a wave plate failure can lead to repeat damage, and it calls for a new pump filter and control solenoid filter plate. Replace the 3-5-R piston and waved plate any time the unit is apart, and inspect the drum splines, since a broken plate often chews them. GEARS recommends replacing the bonded pistons on every rebuild, so plan on the 6T40 bonded clutch piston set alongside this kit. Check the valve body bores while you are in there; worn regulator bores bring back soft shifts no matter how good the clutches are, and the 6T40 valve body is the replacement if they are scored. Because this is a Gen 1 TEHCM, reseal its pressure switches if you reuse it. Install a new converter seal, flush the cooler, fill with Dexron VI, set the level hot at 85-95 C through the check plug, then run the transmission adaptive learn so the TCM starts from a clean baseline.
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Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
It is listed for 2011 applications. The 6T40 family changed for 2012, when most models moved to Gen 2 internals with a five-friction 4-5-6 clutch and no TEHCM pressure switches, although the 2012 Cruze and Sonic 1.8L stayed Gen 1. Match your clutch stack to the kit, or send your VIN and we will confirm.
The two share the same basic layout, and this kit is listed for both across the 2011 Cruze, Regal and LaCrosse engines. The 6T45E is the higher-torque version, so compare the clutch pack count from your unit with the kit before reassembly.
GM PI0780A calls for a new 3-5-R piston and waved plate any time the unit is disassembled, plus a new pump filter and control solenoid filter plate after debris. GEARS also recommends new bonded pistons on every rebuild. Inspect the 3-5-R drum splines and the valve body bores before you order hard parts.
Dexron VI only. Set the final level with the engine running and the fluid at 85-95 C (about 185-203 F) through the check plug, because the 6T40 is easy to overfill and as little as half a quart too much can push fluid out of the vent.
Yes. Run the transmission adaptive values learn with a scan tool after any internal repair. Without it the TCM keeps the old adapts and the rebuilt unit can shift harshly or flare until it relearns.
