6L90 6-Speed Automatic Transmission Assembly for 2012 Chevrolet & GMC

A quick look at your own vehicle makes sure the right transmission shows up:

• Confirm that the 8th digit of your VIN is G (designating the 6.0L L96 gas V8 engine).
• Confirm your truck is a 4x4 (four-wheel drive).
• Open your glove box and find the silver Service Parts Identification (SPID) sticker. Look for the RPO code MYD to confirm the vehicle was built with a 6L90 transmission.
• Confirm your transmission pan has 18 bolts.

What the install really takes — plan and budget with confidence:

Special tools this job needs:

• Transmission jack
• Torque converter holding bracket
• Cooler line flush equipment
• J2534 pass-through programming tool (or GM MDI2) with GM Techline Connect subscription
• Engine support bar
• Torque wrenches
• Fluid pump

Budget for these consumables at install:

• DEXRON-VI Automatic Transmission Fluid (Full Synthetic)
• Transmission Filter Kit (GM Part #24236933 or equivalent filter/seal kit)
• Transmission Pan Gasket
• Torque Converter Seal (Front Pump Seal)
• Transfer Case Input Shaft Seal
• Transmission Cooler Flush (hot-flush or pressurized aerosol flush)

What your vehicle’s computers will need after the swap:

What’s involved: VIN-specific programming (TEHCM/TCM reflash) AND a TCM adaptive relearn (Fast Learn)

The internal TEHCM contains the VIN and software calibration of the donor vehicle. You must reprogram the TEHCM to match your vehicle's exact VIN using GM Techline Connect (SPS2) and a J2534 programming tool (or GM MDI/MDI2). If skipped, the vehicle will experience a 'no-crank' security lockout or go into immediate limp mode. Once programmed, a 'Service Fast Learn' adaptive reset must be performed to prevent harsh shifting and premature clutch wear.

Pro tips for a smooth first start-up — hand them to whoever does the install:

• Torque Converter Seating: The torque converter must be fully seated onto the input shaft and pump gears before bolting the transmission to the engine. You must hear and feel three distinct 'clicks' or drops. Measure the distance from the bellhousing face to the converter pads; it must be recessed at least 1.06 inches. If not fully seated, bolting the transmission to the engine will instantly crack the front pump rotor, destroying the transmission and voiding the warranty.
• Dowel Pin Alignment: Ensure both engine-to-transmission alignment dowel pins are present in the engine block and not stuck in the old transmission. Missing dowels cause misalignment, leading to severe vibration, front pump seal leaks, and cracked flexplates.
• Thermal Bypass Valve: Ensure the external thermal bypass valve in the cooler lines is functioning properly, or install an updated bypass to prevent the transmission from running hot and cooking the TEHCM.
• Cooler Flush is Mandatory: Debris from the old failed transmission will be trapped in the cooler and lines. If not removed, this debris will immediately circulate into the replacement transmission and cause rapid failure.
• Fluid Level Check Procedure: This transmission does not have a traditional dipstick. The fluid level must be checked via a standpipe in the oil pan when the transmission is warm (86°F to 122°F or 160°F to 200°F depending on procedure) and the engine is running in Park on a level lift.

Easy to get right once you know them:

• Assuming 'Plug-and-Play' Operation: Assuming the transmission can be bolted in and driven without reprogramming the internal TEHCM to match the vehicle's VIN.
• Reusing the Old Torque Converter: Reusing the old converter which is filled with contaminated fluid and metal debris from the previous transmission failure.
• Incorrect Fluid Level Check: Checking the fluid cold or with the engine off, leading to inaccurate readings and subsequent slipping or foaming.
• Forcing the Transmission to the Engine: Using the bellhousing bolts to 'pull' the transmission flush to the engine block when the torque converter is not fully seated.

Not issues with the units on this page — the manufacturer documented these for every transmission of this family, wherever you buy one. Handy for your installer: