Transmission Assembly for 2018-2020 Chevrolet Sonic
Product Notes Read before buying
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 | Hatchback | 2018 - 2020 | L4 1.4L Turbo | FWD | Automatic |
| LT | Sedan | 2018 - 2020 | L4 1.4L Turbo | FWD | Automatic |
| Premier | Hatchback | 2018 - 2020 | L4 1.4L Turbo | FWD | Automatic |
| Premier | Sedan | 2018 - 2020 | L4 1.4L Turbo | FWD | Automatic |
| LS | Sedan | 2019 - 2020 | 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:
- Verify the VIN's 8th digit is B (for 1.4L Turbo LUV engine).
- Check the Service Parts Identification label for RPO code MH8 (6T40) or MNU (6T35).
- Confirm the vehicle is Front-Wheel Drive (FWD).
What the install really takes — plan and budget with confidence:
Special tools this job needs:
- Engine Support Bar / Fixture
- Torque Converter Holding Tool (J-46409 or equivalent)
- Bidirectional Scan Tool / GM MDI 2
- Transmission Jack
Budget for these consumables at install:
- DEXRON-VI Automatic Transmission Fluid
- Axle shaft seals (left and right)
- Torque converter hub / front pump seal
- Transmission cooler line flush solvent
- Side cover gasket (only if swapping original TEHCM)
What your vehicle’s computers will need after the swap:
What’s involved: VIN-specific programming (GM Service Programming System / SPS2) and TCM Adaptive Relearn (Service Fast Learn Adapts)
The internal TEHCM/TCM contains the donor vehicle's VIN. It must be reprogrammed using a GM-specific diagnostic tool (like MDI 2) and GM SPS access. Alternatively, the original TEHCM can be swapped onto the replacement unit, which still requires a Service Fast Learn procedure.
Pro tips for a smooth first start-up — hand them to whoever does the install:
- Torque Converter Seating: Must click three times and be recessed at least 1 inch (25mm) from the bellhousing face. Failure to seat fully will crack the internal fluid pump upon engine mating.
- No Dipstick Fluid Fill Procedure: Must check fluid level via the level-set plug on the side of the case with the engine running and fluid temperature at 185°F to 203°F (85°C to 95°C).
- TCM Adaptive Relearn: Must perform 'Service Fast Learn Adapts' before driving to prevent immediate clutch burnout.
- Subframe Removal: The entire front subframe must be lowered or removed to extract the transmission.
- Cooler Line Flush: Mandatory high-pressure flush of the cooler lines to prevent old debris from contaminating the replacement unit.
Easy to get right once you know them:
- Ordering the wrong generation or model (e.g., buying a Gen 1/2 6T40 or confusing 6T40 with 6T35).
- Skipping the transmission cooler line flush.
- Improperly seating the torque converter and cracking the front pump.
- Reusing the old torque converter hub seal.
- Failing to program the TCM/TEHCM to the new VIN.
- Using incorrect fluid types instead of DEXRON-VI.
- Incorrect fluid level checks due to lack of a 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: TCM software calibration update; often normal protective operation to prevent moisture freezing.
🔎 Recommended at install: Replace torque converter or internal lock-up clutch lining.
🔎 Recommended at install: Repair valve body bores or replace valve body to prevent internal hydraulic pressure leaks.
Researched from factory recalls, TSBs and OEM service data (reference unit 400-10311-4086596). 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
2018-2020 Chevrolet Sonic 1.4L Transmission: Problems, Identification, and Used Replacement
A complete breakdown of the 6T35 and 6T40 6-speed automatic transaxles, common failures like torque converter shudder, and how to successfully source and install a used OEM replacement.
Read Full Guide →Related Trouble Codes (OBD-II)
5 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:
Chevrolet: 19332244, 24286647
Fits Years: 2018 2019 2020
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Backed By The Selling Yard
This unit ships with the selling yard's 120-day warranty. Longer plans can be requested during checkout.
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