8-Speed Automatic Transmission Assembly for 2021-2022 Chevrolet & GMC
Product Notes Read before buying
This is an 8-speed automatic transmission for 4x4 models equipped with the 3.6L V6 engine (GM option code M5T). Please verify your vehicle's specifications before ordering.
Voice or type your vehicle details and Wrenchy will confirm fitment in seconds.
Vehicle Fitment Guide
This part fits the following vehicles:
| SubmodelSUB- MODEL |
Body Style | Years | Engine | Attributes |
|---|---|---|---|---|
| LT | Crew Cab Pickup | 2021 - 2022 | V6 3.6L | 4WD | Automatic |
| LT | Extended Cab Pickup | 2021 - 2022 | V6 3.6L | 4WD | Automatic |
| WT | Crew Cab Pickup | 2021 - 2022 | V6 3.6L | 4WD | Automatic |
| WT | Extended Cab Pickup | 2021 - 2022 | V6 3.6L | 4WD | Automatic |
| Z71 | Crew Cab Pickup | 2021 - 2022 | V6 3.6L | 4WD | Automatic |
| Z71 | Extended Cab Pickup | 2021 - 2022 | V6 3.6L | 4WD | Automatic |
| Z71 LT | Crew Cab Pickup | 2021 - 2022 | V6 3.6L | 4WD | Automatic |
| ZR2 | Crew Cab Pickup | 2021 - 2022 | V6 3.6L | 4WD | Automatic |
| ZR2 | Extended Cab Pickup | 2021 - 2022 | V6 3.6L | 4WD | Automatic |
| SubmodelSUB- MODEL |
Body Style | Years | Engine | Attributes |
|---|---|---|---|---|
| AT4 | Crew Cab Pickup | 2021 - 2022 | V6 3.6L | 4WD | Automatic |
| Denali | Crew Cab Pickup | 2021 - 2022 | V6 3.6L | 4WD | Automatic |
| Elevation | Crew Cab Pickup | 2021 - 2022 | V6 3.6L | 4WD | Automatic |
| Elevation | Extended Cab Pickup | 2021 - 2022 | V6 3.6L | 4WD | Automatic |
| Elevation Standard | Crew Cab Pickup | 2021 - 2022 | V6 3.6L | 4WD | Automatic |
| Elevation Standard | Extended Cab Pickup | 2021 - 2022 | V6 3.6L | 4WD | Automatic |
Know This Transmission Before You Buy
The research behind our purchase interview — recalls, bulletins and real install economics for this transmission family:
A quick look at your own vehicle makes sure the right transmission shows up:
- Verify vehicle is a 4x4 / 4WD model with a front driveshaft and transfer case.
- Verify the 8th digit of the VIN is 'N' to confirm the 3.6L V6 (LGZ) engine.
- Verify RPO code 'M5T' is listed on the silver Certification Label on the door jamb or the SPID label in the glove box.
What the install really takes — plan and budget with confidence:
Special tools this job needs:
- Heavy-duty transmission jack
- J2534 pass-thru programming tool or GM-compatible diagnostic scan tool (GM MDI/MDI2/GDS2)
- GM Pass-through Connector Harness Removal Tool
- Fluid transfer pump / exchange machine
- Precision torque wrench
Budget for these consumables at install:
- Mobil 1 Synthetic LV ATF HP (Blue Label) fluid (approx. 10 to 11.4 quarts for dry fill/overhaul; up to 20 quarts for full flush)
- Transmission filter (ACDelco TF922 or equivalent)
- Oil pan gasket (GM 24260071)
- Front torque converter / pump input shaft seal
- Rear output shaft seal
- Professional-grade transmission cooler flush solvent
What your vehicle’s computers will need after the swap:
What’s involved: Solenoid Valve Characterization Reprogramming (MCVM) and Transmission Service Fast Learn
The TCM must be programmed with the Transmission Unique Number (TUN) from the replacement unit's case sticker using GM's SPS2 system to download the correct solenoid characterization data. A Fast Learn procedure must then be run to reset clutch adaptive values. Skipping this can physically destroy the internal clutches within a few miles.
Pro tips for a smooth first start-up — hand them to whoever does the install:
- Torque converter must be fully seated (three distinct drops/clicks, recessed about 1 inch) before bolting transmission to engine to prevent cracking the front oil pump rotor.
- Exhaust Y-pipe runs directly beneath the transmission pan and must be loosened/dropped slightly for clearance.
- Fragile 20-way electrical connector can crack easily if pried with a screwdriver.
- No dipstick is present; fluid level must be checked via the standpipe plug in the bottom of the pan at operating temperature (95°F to 113°F) with the engine running in Park.
Easy to get right once you know them:
- Using standard Dexron VI or generic multi-vehicle fluid instead of Mobil 1 Synthetic LV ATF HP (Blue Label), causing immediate torque converter shudder.
- Attempting to drive the vehicle without programming the replacement transmission's TUN into the TCM, leading to severe shift issues and clutch damage.
- Reusing a contaminated torque converter or failing to flush the cooler lines, which introduces debris into the replacement unit.
- Failing to fully seat the torque converter before tightening bellhousing bolts, resulting in a cracked front pump.
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:
🔎 Recommended at install: Complete fluid exchange using Mobil 1 Synthetic LV ATF HP (Blue Label). If physical damage or glazing has occurred, replace the torque converter.
🔎 Recommended at install: Install updated stator support and case cover with an additional check ball to prevent drain-back.
🔎 Recommended at install: Perform Transmission Service Fast Learn procedure using a GM-compatible diagnostic scan tool, followed by a road-test adaptive relearn. Internal mechanical wear may require valve body service.
Researched from factory recalls, TSBs and OEM service data (reference unit 400-11144-5560646). Unit-specific details — mileage, condition, warranty, freight — are covered in the checkout interview.
Policies, in plain English.
Shipping & Handling
- Ships by LTL freight on a pallet — a real freight truck, not a parcel van
- Your checkout freight quote covers delivery to your door (liftgate service included for residential addresses)
- The carrier calls ahead to schedule a delivery window — someone must be present to receive it
- Typically palletized and picked up within 2–3 business days; transit time depends on distance
120-Day Warranty
This part includes a 120-day warranty.
- If the part fails within the warranty window, we'll replace it or refund per the coverage terms
- Coverage is parts-only — installation labor is not included
- Warranty covers defects — not installation errors, misuse, or damage after installation
Your pre-purchase interview reviews these exact terms with you before anything is charged.
Returns (30 Days)
We accept returns of uninstalled parts within 30 days of delivery for this part.
- Defective parts: We will replace the part or issue a refund at our discretion
- Programming: "Needs to be programmed to my vehicle" is not a valid return reason. Many modules require dealer programming — we're happy to help connect you with resources if your dealer says it's not programmable
- Return shipping: This part ships by freight (LTL) — the part price is refundable per the terms above, but shipping costs are non-refundable and return freight follows the seller's return terms. Your pre-purchase interview walks through the exact numbers before you buy
- Parts must be returned in original packaging and unmodified condition
- Poorly packaged returns that arrive damaged will not be credited
Damaged in Shipping?
Freight damage is rare — and you're fully protected when you do two things at delivery:
- Inspect before you sign — you're allowed time to look the pallet over while the driver waits
- Write any damage on the delivery receipt before signing — that one line is what makes a freight claim succeed
- Severe damage? Refuse the delivery — it goes back at no cost to you and we make it right
- Photograph the pallet before unwrapping; report concealed damage within 24 hours of delivery
We handle the carrier claim — you just help document it. Your pre-purchase interview walks through this checklist too.
Order Cancellation
Cancel before shipment for a full refund. Once the pallet has been built, a preparation charge may apply — and once the freight carrier picks it up, shipping costs are non-refundable and standard return terms apply. Your pre-purchase interview shows the exact numbers before you pay.
Expert Guides
2021-2022 Colorado & Canyon 3.6L 8L45 Transmission: Problems, Identification, and Used Replacement
Identify the exact M5T 8-speed automatic, understand the notorious torque converter shudder, and learn what to look for when buying a used replacement unit.
Read Full Guide →Related Trouble Codes (OBD-II)
9 matching guidesIf your scan tool is showing one of these trouble codes, this part is a common fix. Each guide explains the code, how to diagnose it, and exactly what to replace.
Miscellaneous Information
OEM Part Numbers:
GM: 19434562, 24290742
Fits Years: 2021 2022
Your Go-To Place
for auto parts.
In operation since 2007. Trusted by over a million DIYers, mechanics, and body shops across all 50 states.
Confirmed Before It Ships
Every freight order is confirmed through a short guided interview — fitment, condition, delivery and warranty terms, e-signed before you're charged.
Trusted Since 2007
Nearly two decades of shipping parts to professionals & enthusiasts.
Backed By The Selling Yard
This unit ships with the selling yard's 120-day warranty. Longer plans can be requested during checkout.
What buyers are saying.
Racing Partner Videos
