6T40 Gen 2 Transmission Valve Body Casting MH7 MH8

The 6T40 and its wider brother the 6T45 are the six-speed front-drive units GM hung behind the 2.4L Ecotec and the 1.4L turbo, and the valve body is the part of the transmission that takes the abuse. The bores that feed the 1-2-3-4 and 3-5-reverse clutch circuits wear oval, the separator plate checkballs pound their seats, and pressure that should be holding a clutch applied leaks past the valve instead. What the driver feels is a harsh or banging 1-2, a flare between second and third, a slip under light throttle at cruise, or a delayed engagement into drive on a cold start. What the scan tool shows is usually P0776, P0777, P0796, P0842 or P0843 with pressure-control ratio faults that keep coming back after a solenoid replacement. Once the bore is worn, cleaning the solenoids does not restore the pressure.

This is the Generation 2 aluminum valve body casting for RPO codes MH7, MH8, MHH and MHC, covering 2012-2017 Chevrolet Cruze, Equinox and Malibu, Buick Regal, Verano and LaCrosse, and GMC Terrain with the 2.4L four or the 1.4L turbo. Read the RPO label in your glove box before you order: MH7, MH8, MHH and MHC are the Gen 2 units this casting fits. MNH and MNK are the Gen 3 start/stop units and will not interchange, the 2008-2010 Gen 1 body is a different casting, and the 3.0L and 3.6L V6 cars use the 6T50 or 6T70, which is a larger unit entirely.

Important on what you are buying: this is the casting only. It ships without solenoids, without the TEHCM control module, without pressure switches and without wiring. You transfer those parts off your original body, which is normally what you want anyway, because the TEHCM is VIN-married to the vehicle and a swapped module means a trip to a scan tool that can program it. Plan on a new separator plate gasket set, a new filter and a fresh fill of DEXRON VI while the pan is off.

On the bench, pull the pan and filter, then photograph the solenoid and TEHCM harness routing before you disturb anything. Move the solenoids across one at a time so nothing ends up in the wrong bore, keep the checkballs and the separator plate oriented exactly as they came out, and seat the manual valve on the detent lever pin before you snug any bolts. Torque the valve body bolts evenly from the center outward to the figure in your service manual rather than running them down in a circle, or the casting will distort and cross-leak. After the fluid fill, clear codes and let the TEHCM relearn the shift adaptives over a few miles of light-throttle upshifts.