Transmission Assembly for 2016-2020 Kia Optima
Product Notes Read before buying
This transmission fits specific vehicles based on VIN. For 2016-2018 models, the 8th digit of the VIN must be '2'. For 2019-2020 models, the vehicle must be US-built (1st VIN digit '5'). Please verify your vehicle's VIN to ensure compatibility.
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 |
|---|---|---|---|---|
| SX | Sedan | 2016 - 2020 | L4 2.0L Turbo | FWD | Automatic |
| SX Limited | Sedan | 2016 - 2017 | L4 2.0L Turbo | FWD | Automatic |
| SXL | Sedan | 2016 - 2020 | L4 2.0L Turbo | FWD | Automatic |
| SX Turbo | Sedan | 2018 - 2019 | L4 2.0L Turbo | FWD | Automatic |
| SXL Turbo | Sedan | 2018 - 2019 | L4 2.0L 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 the VIN is '2' (2.0L Turbo engine).
- Verify if the vehicle is US-built (1st digit of VIN is '5').
- Locate the barcode sticker on top of the bellhousing to match OE part numbers 45000-3BTA0 or 45000-3BTA0R.
What the install really takes — plan and budget with confidence:
Special tools this job needs:
- Engine support bar
- Subframe jack or transmission jack
- OBD2 scan tool with Kia/Hyundai bidirectional capabilities
Budget for these consumables at install:
- Hyundai/Kia ATF SP-IV fluid
- Input shaft/pump seal (torque converter seal)
- Axle seals
- Transmission cooler flush kit
What your vehicle’s computers will need after the swap:
What’s involved: TCU adaptive value reset and solenoid characteristic value entry
sources differ: Arm 1 identifies the unit as A6LF2 requiring an adaptive reset; Arm 2 identifies it as A6MF2 requiring both an adaptive reset and manual entry of solenoid characteristic values from the barcode sticker using a Kia KDS tool — confirm with us before install
Pro tips for a smooth first start-up — hand them to whoever does the install:
- Torque converter must be fully seated (typically three distinct clicks) before bolting to the engine to avoid cracking the oil pump gear.
- Front subframe must be partially lowered or removed, requiring an engine support bar from above.
- Fluid level must be checked at 50-60°C (122-140°F) via the overflow plug on the front plastic cover while the engine is running.
- Solenoid calibration data from the barcode sticker must be programmed into the TCU on newer models.
- Axle seals are easily nicked during CV axle insertion, causing immediate leaks.
Easy to get right once you know them:
- Reusing a contaminated transmission cooler without flushing, which destroys the replacement unit's valve body.
- Skipping the TCU adaptive values reset and solenoid calibration, leading to violent shifting and immediate clutch damage.
- Using generic or incorrect ATF instead of OE-spec SP-IV fluid.
- Failing to fully seat the torque converter, resulting in a broken front pump upon bellhousing bolt tightening.
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: Update Transmission Control Unit (TCU) software logic.
🔎 Recommended at install: TCU software reflash to address harsh shifting and delays.
🔎 Recommended at install: Repair or replace valve body to address wear at reducing valves #1 and #2.
🔎 Recommended at install: Replace internal wiring harness and integrated fluid temperature sensor.
Researched from factory recalls, TSBs and OEM service data (reference unit 400-63226-5506654). 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
2016-2020 Kia Optima 2.0L Turbo Transmission: Problems, Identification, and Used Replacement
Identify the exact A6 family transaxle, learn what causes harsh shifting, and discover 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:
Kia: 450003BTA0, 450003BTA0R
Fits Years: 2016 2017 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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