Transmission Assembly for 2015 Buick & Chevrolet • Encore, Sonic, Trax - Front
Product Notes Read before buying
This transmission fits only Front-Wheel Drive (FWD) models with the 1.4L turbocharged engine. For Chevrolet Sonic, it is specific to the RS trim level. It is essential to verify that your vehicle is equipped with the 6-speed automatic transmission (RPO code MH8) and a 3.53 final drive ratio (RPO code FXH) 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 |
|---|---|---|---|---|
| Base | SUV | 2015 | L4 1.4L Turbo | FWD | Automatic |
| Convenience | SUV | 2015 | L4 1.4L Turbo | FWD | Automatic |
| CX | SUV | 2015 | L4 1.4L Turbo | FWD | Automatic |
| CXL | SUV | 2015 | L4 1.4L Turbo | FWD | Automatic |
| Leather | SUV | 2015 | L4 1.4L Turbo | FWD | Automatic |
| Premium | SUV | 2015 | L4 1.4L Turbo | FWD | Automatic |
| SubmodelSUB- MODEL |
Body Style | Years | Engine | Attributes |
|---|---|---|---|---|
| RS | Hatchback | 2015 | L4 1.4L Turbo | FWD | Automatic |
| RS | Sedan | 2015 | L4 1.4L Turbo | FWD | Automatic |
| SubmodelSUB- MODEL |
Body Style | Years | Engine | Attributes |
|---|---|---|---|---|
| LS | SUV | 2015 | L4 1.4L Turbo | FWD | Automatic |
| LT | SUV | 2015 | L4 1.4L Turbo | FWD | Automatic |
| LTZ | SUV | 2015 | L4 1.4L Turbo | FWD | 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:
- Confirm the 8th digit of your VIN is 7 or B (matching the 1.4L Turbo engine).
- Confirm the vehicle is Front-Wheel Drive (FWD).
- Locate the Service Parts Identification label (glove box or spare tire well) and confirm RPO codes MH8 (transmission) and FXH (3.53 final drive ratio).
What the install really takes — plan and budget with confidence:
Special tools this job needs:
- Engine support fixture
- Transmission jack
- Subframe cradle jack
- GM-compatible J2534 programming tool (e.g., GM MDI) with active ACDelco TDS subscription
- Bidirectional scan tool capable of performing GM Fast Learn
Budget for these consumables at install:
- DEXRON-VI Synthetic Automatic Transmission Fluid
- New CV axle seals (half-shaft seals)
- New torque converter seal (front pump seal)
- Aerosol transmission cooler line flush (e.g., Lubegard Kooler Kleen)
What your vehicle’s computers will need after the swap:
What’s involved: VIN-specific programming (SPS / Service Programming System), Solenoid Characterization (MCVM data entry), and a TCM Adaptive Relearn (Fast Learn).
The integrated TEHCM (TCM) is electronically married to the vehicle's VIN. If you install this transmission without programming it, the vehicle will not start, or it will immediately enter 'limp-home' mode. A dealer-level scan tool or a mobile programming service must flash your vehicle's VIN to the TCM and download the specific solenoid flow rate data (Solenoid Characterization) matching this transmission's unique barcode/TUN number. After programming, a 'Transmission Adaptive Values Learn' (Fast Learn) must be performed.
Pro tips for a smooth first start-up — hand them to whoever does the install:
- Torque Converter Seating: Ensure the torque converter is fully seated onto the transmission input shaft and pump gears (must click/drop down three distinct times) before bolting to the engine. Tightening bellhousing bolts on an unseated converter will shatter the internal oil pump gear.
- Solenoid Characterization Code: The technician must enter the 12-digit Solenoid Characterization code (TUN/MCVM code) printed on the transmission case barcode label during programming.
- Fluid Level Check Procedure: There is no dipstick. The vehicle must be perfectly level, engine running, and transmission fluid temperature strictly between 85°C and 95°C (185°F to 203°F) when removing the level set plug near the axle. Checking outside this window causes incorrect fluid levels.
- Internal Filter: The transmission filter is located internally in the sump and cannot be replaced without splitting the transmission case. Do not attempt to replace it during standard installation.
- Mandatory Adaptive Relearn: You must perform the Fast Learn procedure with a scan tool before driving to prevent harsh shifting and clutch damage.
Easy to get right once you know them:
- Mistaking FWD vs. AWD: AWD versions have a completely different case casting to accommodate the transfer case and are incompatible with this FWD unit.
- Skipping the Programming Step: Attempting to drive without programming the TEHCM causes a no-start condition, immediate limp mode, or severe transmission damage.
- Reusing Your Old TEHCM to Avoid Programming: Swapping an old, potentially contaminated TEHCM onto the replacement transmission introduces debris and carries over original shifting issues.
- Reusing Clogged Cooler Lines: Failing to flush cooler lines sends metal shavings from the failed transmission straight into the replacement unit, destroying solenoids and the valve body.
- Incorrect Fluid Leveling: Draining and filling without following the temperature-dependent check-plug procedure leads to severe underfilling or overfilling.
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 defective electronic park lock lever to prevent ignition key removal when not in PARK.
🔎 Recommended at install: Replace or rebuild TEHCM; clean debris and address diagnostic trouble codes P0752, P0776, or P0796.
🔎 Recommended at install: Replace fractured 3-5-Reverse clutch wave plate to restore reverse gear and correct slipping/harsh shifts.
🔎 Recommended at install: Perform fluid flush or replace torque converter clutch.
Researched from factory recalls, TSBs and OEM service data (reference unit 400-05137-1877968). 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
2015 Trax, Encore & Sonic 1.4L 6T40 Transmission: Problems, Identification, and Used Replacement
Identify the correct MH8 transaxle, diagnose common TEHCM and shift flare failures, and learn what to check before buying a used replacement unit.
Read Full Guide →Related Trouble Codes (OBD-II)
14 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: 19354006, 24263660
Other: 5SAW
Fits Years: 2015
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This unit ships with the selling yard's 120-day warranty. Longer plans can be requested during checkout.
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