6T40 Master Rebuild Kit 2012, new and ready to install. Fits the 6T40. Ships fast from the USA.
A 2012 Chevrolet Cruze, Sonic, Malibu, Buick Verano or other GM front-driver with a 6T40 that slips, has lost reverse, flares between gears or leaves burnt clutch material in the pan has usually reached the point where a full overhaul is cheaper than chasing one clutch at a time. This new master rebuild kit is built for 2012 6T40 units and covers the frictions, steels, seals and gaskets for a complete teardown. The catch with a 2012 is that it is the changeover year, so the most important step happens before you order: confirming which generation you have.
The 6T40 runs five clutches through a TEHCM, the TCM and solenoid body built into one assembly inside the case. For 2012, GM rolled out the Gen 2 update described in Preliminary Information PI0604C: the fluid pressure switches came out of the TEHCM, the valve body gained actuator feed accumulators and revised regulator valves, one 3-5-R/4-5-6 seal ring left the case, and the 4-5-6 clutch got a revised piston, return spring and fluid dam with five frictions instead of four. A master kit replaces the wear material in all five clutches and reseals every circuit, but the 4-5-6 friction count and the seal ring layout have to match the generation of your case.
GM's PI0670A spells out the 2012 split. Gen 1 controls stayed in the Cruze and Sonic with the 1.8L, the Captiva Sport 3.0L and the Orlando. Gen 2 went into the Cruze 1.4L turbo, the Sonic 1.4L, the Captiva Sport 2.4L, Equinox, Malibu, Terrain, LaCrosse, Regal and Verano. Because two Cruzes from the same year can carry different internals, read the TEHCM label: per Sonnax, the eighth digit under the bar code is 1, 2 or 3 on Gen 1 and B, C or D on Gen 2.
Rule out the inexpensive causes first. Check the fluid level hot, because an overfill can push fluid out of the vent and set P0218. On a 2012 Cruze 1.8 with a hesitation and bump on launch, GM's PI0640 traces it to the Neutral Idle calibration, which is a reflash, not a rebuild. If the pan shows steel or clutch debris and the codes line up, the unit needs to come apart. Our 6T40 delayed engagement guide and the 6T40 common problems and fixes walk through the checks in order.
This kit is listed for the 6T40 in 2012 applications. Match the clutch count, 4-5-6 drum and seal rings in your case to the kit, or send us your year and VIN before ordering. For a 2008-2011 unit, the 2008-11 6T40 master rebuild kit is the better starting point, and for a 6T45 in an Equinox or Terrain see the 2012 6T45 master kit. Every other option is on the rebuild kit category page.
Replace the 3-5-R piston and waved plate on every teardown, as GM PI0780A recommends, and check the drum splines for damage from any earlier plate failure. Do not reuse the bonded pistons; GEARS ties the falls-out-of-gear complaint to a cracked 1-2-3-4 piston. Inspect the low one-way clutch and the reaction shell while the unit is apart, and if the sprag freewheels both ways or shows scored races, compare it with the 6T40 sprag clutch listing before ordering. If the case is Gen 1, reseal the TEHCM pressure switches before you reuse it. GM PI0950 also recommends the revised converter seal any time the transmission is out. Fill with Dexron VI, set the level at 85-95 C through the check plug, and run the adaptive learn before the first real drive.
| Fits | 6T40 2012 |
| Part type | Master Rebuild Kit |
| Condition | New |
| Brand | GM |
| Ships | From the USA |
| Warranty | 1-year |
Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
Read the TEHCM label. Sonnax gives the eighth digit under the bar code as 1, 2 or 3 for Gen 1 and B, C or D for Gen 2. GM PI0670A also lists the 2012 Cruze and Sonic 1.8L, Captiva Sport 3.0L and Orlando as Gen 1, and most other 2012 models as Gen 2.
It renews the 3-5-R frictions and seals, which is part of the fix. No reverse with P0776 usually means a broken 3-5-R waved plate or cut piston lips, so add a new 3-5-R piston and waved plate, inspect the drum splines and clean all debris from the case.
Dexron VI only. GM lists 4.2-6.3 quarts for a fluid change, but a rebuilt unit filled from dry with the converter takes more. Set the final level hot, at 85-95 C, through the check plug.
No. GEARS documents that a Gen 2 drum in a Gen 1 case may pass a road test but leaves the compensator feed regulator without its inner seal, leading to falling out of gear at a stop, low line pressure and clutch failure.
Run the transmission adaptive learn after any internal repair. If you also replace the TEHCM, it must be programmed to the vehicle with the correct calibration, and a wrong-generation TEHCM can set P0713 or P06AE.
