Transmission Assembly for 2020-2023 Hyundai Sonata
Product Notes Read before buying
This transmission fits Front-Wheel Drive (FWD) models only. It is specifically for vehicles equipped with the 1.6L turbo engine.
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 |
|---|---|---|---|---|
| Limited | Sedan | 2020 - 2023 | L4 1.6L Turbo | FWD | Automatic |
| Luxury | Sedan | 2020 - 2022 | L4 1.6L Turbo | FWD | Automatic |
| SEL Plus | Sedan | 2020 - 2023 | L4 1.6L Turbo | FWD | Automatic |
| Sport | Sedan | 2020 - 2023 | L4 1.6L Turbo | FWD | Automatic |
| Ultimate | Sedan | 2020 - 2021 | L4 1.6L 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 8th digit of the VIN is 'D' (designating the 1.6L Turbo G4FP engine).
- Confirm the vehicle has a push-button electronic gear selector (Shift-by-Wire) on the center console.
- 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
- Transmission jack
- Subframe alignment pins
- Advanced OBD-II scan tool with Hyundai/Kia OEM-level programming capabilities
Budget for these consumables at install:
- Hyundai Genuine ATF SP4-M / SP-IV fluid (approx. 7 to 9 quarts for full replacement)
- Internal transmission filter and plastic oil pan gasket (Part # 45283-4G***)
- Input shaft / torque converter hub seal
- Axle seals
- High-pressure transmission cooler and warmer line flush
What your vehicle’s computers will need after the swap:
What’s involved: TCM Adaptive Relearn and Oil Pressure Characteristics Input (Solenoid Valve Calibration)
Requires inputting the unique 8-character alphanumeric solenoid flow characteristic codes stamped on the replacement transmission's solenoids into the TCM using a dealer-level scan tool (Hyundai GDS or equivalent). Additionally, TCM adaptive values must be reset followed by a specific driving relearn procedure.
Pro tips for a smooth first start-up — hand them to whoever does the install:
- Torque converter must click three times to seat fully. Failure to seat it completely before bolting to the engine will crack the internal oil pump gear.
- The front subframe must be dropped for clearance, requiring steering/suspension disconnection and subframe alignment pins.
- Fluid level must be checked via the overflow plug on the side of the plastic oil pan only when fluid temperature is strictly between 122°F and 140°F (50°C - 60°C).
- Skipping the solenoid flow code programming or adaptive value reset will cause harsh shifting, slipping, and premature transmission failure.
Easy to get right once you know them:
- Confusing the 1.6L Turbo's 8-speed automatic (A8MF1 torque converter) with the 2.5L Turbo N-Line's 8-speed wet dual-clutch transmission (DCT).
- Using generic multi-vehicle ATF or DCT fluid instead of Hyundai Genuine ATF SP4-M / SP-IV.
- Failing to perform the solenoid calibration (Oil Characteristics Input) in the TCM.
- Reusing a contaminated transmission cooler/warmer without a professional high-pressure flush, which washes metal debris back into the new unit.
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 the porous rear cover of the transmission.
🔎 Recommended at install: If DTCs P0731-P0736, P0729, P076F, or P0730 are present and slippage is confirmed, replace the entire transmission assembly.
🔎 Recommended at install: Replace the faulty internal valve body wiring harness and affected solenoid.
🔎 Recommended at install: Software update for the TCU or transmission replacement if DTC P1C2D03 is present. Note: Sources differ on applicability; Arm 1 states this traditional torque-converter A8MF1 is completely unaffected, while Arm 2 notes it as a major issue for this type of transmission.
Researched from factory recalls, TSBs and OEM service data (reference unit 400-11119-5050768). 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
2020-2023 Hyundai Sonata 1.6L Turbo A8MF1 Transmission: Problems, Identification, and Used Replacement
Identify the exact A8MF1 8-speed automatic, understand what causes internal clutch failure, and learn when to replace it with a used OEM unit.
Read Full Guide →Related Trouble Codes (OBD-II)
4 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:
Hyundai: 450004G621
Fits Years: 2020 2021 2022 2023
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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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