6-Speed Automatic Transmission Assembly for 2015 Kia Optima
Product Notes Read before buying
This is a 6-speed automatic transmission for 2015 Kia Optima models with a 2.4L engine. It fits US-built vehicles with the 8th digit of the VIN as '7', manufactured from 08/18/2014 onwards. Please verify your vehicle's VIN and production date 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 |
|---|---|---|---|---|
| EX | Sedan | 2015 | L4 2.4L | FWD | Automatic |
| EX Luxury | Sedan | 2015 | L4 2.4L | FWD | Automatic |
| Hybrid EX | Sedan | 2015 | L4 2.4L FULL HYBRID EV-GAS (FHEV) | FWD | Automatic |
| Hybrid LX | Sedan | 2015 | L4 2.4L FULL HYBRID EV-GAS (FHEV) | FWD | Automatic |
| LX | Sedan | 2015 | L4 2.4L | FWD | Automatic |
| SX | Sedan | 2015 | L4 2.4L | 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 1st digit of the VIN is 5 (US-built).
- Confirm the 8th digit of the VIN is 7 (2.4L naturally aspirated engine).
- Verify the OEM part number on the transmission tag matches 45000-3B744.
- Confirm the vehicle production date on the door jamb is on or after August 18, 2014.
What the install really takes — plan and budget with confidence:
Special tools this job needs:
- Engine support bar / hoist
- Heavy-duty transmission jack
- Subframe support jacks
- 32mm axle nut socket
- Pry bars
- Bidirectional OBD-II scan tool (KDS)
Budget for these consumables at install:
- Kia Genuine ATF SP-IV (SP-4) or fully synthetic equivalent (7.1 to 8.3 Quarts total capacity)
- Torque converter hub seal (front pump seal)
- Axle shaft (half-shaft) seals
- Transmission filter and pan gasket (Arm 2)
- Chemical transmission cooler line flush
What your vehicle’s computers will need after the swap:
What’s involved: TCM Adaptive Relearn
sources differ: Arm 1 states no VIN-specific programming is required but a TCM adaptive relearn is mandatory. Arm 2 states programming is required in the form of a TCM adaptive relearn, and a dealer-level scan tool is required for best results. Cautious value 'yes' selected.
Pro tips for a smooth first start-up — hand them to whoever does the install:
- The Torque Converter 'Three-Click' Rule: Ensure the torque converter is fully seated (three distinct clicks) to avoid crushing the internal oil pump gear upon tightening bellhousing bolts.
- Sealed Fluid Level Check Procedure: Must check fluid level with engine running at 122-140°F (50-60°C) via the overflow plug on the side cover. Checking with engine off will cause severe underfilling.
- Ensure alignment dowel pins in the engine block are clean and present to prevent input shaft bearing wear.
- Transmission cooler and lines must be professionally flushed to prevent old debris from contaminating the replacement unit.
Easy to get right once you know them:
- Ordering for a Korean-built Optima (VIN starting with K) instead of US-built (VIN starting with 5).
- Assuming all 2015 Optima transmissions are identical (ordering for 2.0L Turbo or 2.4L Hybrid instead of naturally aspirated 2.4L).
- Skipping the TCM adaptive values reset, leading to immediate harsh shifting and clutch burnout.
- Checking the fluid level with the engine turned off, resulting in a severely underfilled transmission.
- Reusing contaminated cooler lines without performing a chemical flush.
- Using incorrect or universal multi-vehicle ATF instead of genuine SP-IV fluid.
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 internal temperature sensor (Part #46386-3B900) on the bench before installation.
🔎 Recommended at install: Perform TCM adaptive values reset and apply latest TCM software updates.
🔎 Recommended at install: Thoroughly flush transmission cooler lines and use fresh, high-quality fluid.
🔎 Recommended at install: Avoid frequent wheel slippage; maintain proper fluid levels.
Researched from factory recalls, TSBs and OEM service data (reference unit 400-63196-2399119). 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 Kia Optima 2.4L A6MF Transmission: Problems, Identification, and Used Replacement
Identify the exact US-built A6MF transaxle, learn what causes harsh shifting and sensor failures, and discover when replacing with a used OEM unit is the smartest fix.
Read Full Guide →Related Trouble Codes (OBD-II)
19 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: 450003B744, 450003B744R
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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