9-Speed Automatic Transmission Assembly for 2018-2022 GMC Terrain
Product Notes Read before buying
This is a 9-speed automatic transmission for All-Wheel Drive (AWD) models equipped with the 1.5L engine only. It will not fit Front-Wheel Drive (FWD) vehicles or models with other engine sizes. Please verify your vehicle's specifications prior to 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 |
|---|---|---|---|---|
| AT4 | SUV | 2022 | L4 1.5L Turbo | AWD | Automatic | Hollander: TERRAIN 18-20 (AT), AWD, 1.5L | TERRAIN 21 (AT), AWD | TERRAIN 22 (AT), AWD, ID 24283828; drive_type: include AWD; engine_size: include 1.5L; transmission: include Automatic; transmission_speeds: include 9 |
| 2018 - 2021 |
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 VIN 8th digit is V (1.5L LYX Turbo engine).
- Physically confirm vehicle is All-Wheel Drive (AWD) by checking for a rear driveshaft and rear differential.
- Scan the QR code label on the driver's side B-pillar to verify transmission RPO code is M3U.
What the install really takes — plan and budget with confidence:
Special tools this job needs:
- Engine support fixture
- Transmission jack
- Torque converter alignment tool
- GM-compatible scan tool (MDI2 / GDS2)
- Drive axle boot protectors
- GM-specific tool DT-47797
Budget for these consumables at install:
- ACDelco DEXRON-VI synthetic automatic transmission fluid
- New transmission filter kit with new pan gasket
- Input shaft/torque converter seal
- Axle seals
- Transmission cooler line flush solvent
What your vehicle’s computers will need after the swap:
What’s involved: VIN-specific programming, Transmission Unique Number (TUN) / Part Unique Number (PUN) characterization, and Transmission Fast Learn (adaptive relearn).
Requires online programming using GM's SPS2 (Service Programming System) via Techline Connect, a J2534 pass-thru device, and a stable power supply to input the 16-digit TUN from the replacement transmission case. An adaptive pressure learn procedure must also be performed.
Pro tips for a smooth first start-up — hand them to whoever does the install:
- Torque Converter Seating: Must hear and feel three distinct clicks/drops. If not fully seated, bolting to the engine will crush the internal oil pump.
- Document the TUN/PUN Before Installation: The 16-digit TUN is etched on the case and is nearly impossible to read once installed.
- Fluid Level Check Procedure: No dipstick. Must check using the leveling plug on the side of the case while idling, vehicle level, and fluid temp precisely between 175°F and 203°F.
- AWD Alignment: Ensure the intermediate shaft and transfer housing align perfectly with the right-side axle to avoid damaging splines or differential seals.
- Start/Stop Accumulator: Handle carefully and check for missing bolts related to the recall.
Easy to get right once you know them:
- Skipping the TUN/PUN Programming: Attempting to drive without programming causes severe shift shocks, slipping, and immediate clutch damage.
- Ordering FWD instead of AWD: FWD transmission cases lack mounting provisions and output shaft setups for the AWD transfer unit.
- Reusing Old, Contaminated Fluid or failing to flush cooler lines: Sends metal shavings from the failed unit directly into the new unit's solenoids.
- Improper Torque Converter Bolt Torque: Reusing stretched bolts or over-tightening them can strip threads or cause them to back out.
- Improper Fluid Level Check: Checking fluid level cold or with the engine off due to lack of a traditional dipstick.
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: Replace snap ring; typically sets DTCs P0746 or P0747.
🔎 Recommended at install: Solenoid clips fatigue and stretch, allowing solenoids to back out of their bores. Requires valve body service.
🔎 Recommended at install: Often related to torque converter or internal planetary gear alignment.
🔎 Recommended at install: Resolved via TCM software update.
🔎 Recommended at install: Resolved via TCM software update.
🔎 Recommended at install: Inspect case for slow, hard-to-trace transmission fluid leaks.
🔎 Recommended at install: Dealers inspect the accumulator and replace it if bolts are missing.
🔎 Recommended at install: Feels like a vibration or 'fish bite'.
Researched from factory recalls, TSBs and OEM service data (reference unit 400-10937-5012552). 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
2018-2022 GMC Terrain 1.5L AWD Transmission: Problems, Identification, and Used Replacement
Identify the GM 9T45 (M3U) transmission, learn what causes it to fail, and discover when replacing it with a used OEM unit is the smartest choice.
Read Full Guide →Related Trouble Codes (OBD-II)
3 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:
GMC: 22984721, 24283828
Fits Years: 2018 2019 2020 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
