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Jul 20, 2026 / By Edas Petrauskas / in Automotive Guides
The Mitsubishi Evo X MR SST transmission is one of the most important and least forgiving assemblies in the car. The six-speed twin-clutch unit delivers the quick, decisive shifts that define the MR driving experience, but it also depends on correct identification, software compatibility, fluid condition and careful installation. Part number 2500A343 is associated with the later 2011–2015 Evolution X MR SST application, making it a key reference for anyone replacing a failed unit or planning a factory-correct restoration.
This guide is written for owners, workshops and parts buyers who need to make a controlled decision rather than buy from a title alone. The product number, the vehicle configuration and the condition of the surrounding components matter as much as the name of the assembly. Start with the factory information, compare it with the part in the vehicle and only then decide whether the listed component is the correct solution.
Mitsubishi OEM SST MR Transmission 2500A343 for 2011–2015 Evo X is the exact product discussed here. Before placing an order, compare the SKU, visible casting or identification marks, vehicle data and the complete list of parts included. A product image is useful for orientation, but it is not a substitute for confirming fitment.
| Reference | Details to verify |
|---|---|
| Product SKU | MIT-2500A343 |
| Primary application | 2011–2015 Mitsubishi Lancer Evolution X MR with SST |
| Category | Mitsubishi performance parts |
| Decision rule | Confirm VIN, original part number, software or supporting hardware where applicable. |
2500A343 is the later OEM reference used for the 2011–2015 Evolution X MR SST transmission. The unit is identified in the supplied cross-reference as transmission code W6DGA-4-11A with TCM software part number 8631A971. Those details matter because an Evo X SST is not a conventional manual gearbox with a simple bolt-in replacement process. It is a dual-clutch transmission with an integrated control strategy. The mechanical unit, transmission control module, wiring, sensors, clutch operation and vehicle calibration all have to agree.
Earlier Evo X MR variants use different references. The 2008 model is listed with 2500A137 and W6DGA-1-11A, the 2009 application with 2500A277, and the 2010 version with 2500A305. Some of these numbers may be cross-referenced in service information, but that does not mean a buyer should assume direct interchangeability. Confirm the exact vehicle year, MR specification and original label before selecting a replacement.
An SST replacement is normally considered after a major internal problem, persistent shift fault, clutch-related issue or damage that makes rebuilding impractical. Symptoms can include harsh engagement, refusal to select a gear, limp mode, abnormal noise, leaks or fault codes. None of those symptoms proves that the complete transmission is failed. Low fluid level, contaminated fluid, a damaged connector, a weak battery, wiring faults or calibration problems can create similar behaviour. A proper diagnostic report should come before an expensive major-parts decision.
When the diagnosis does point to the transmission, the next question is whether the replacement is new OEM, rebuilt or used. A new OEM assembly offers a defined factory reference, but availability and cost can be substantial. A rebuilt unit can be attractive when the rebuilder documents the work, clutch components, valve-body condition and warranty terms. A used unit needs the strongest evidence of its donor application, history and condition. In every case, the correct part number remains the starting point.
Do not stop at the big number cast into a housing or copied into a marketplace title. Record the complete code on the existing unit and compare the TCM software reference where available. The 2500A343 listing is associated with W6DGA-4-11A and 8631A971. This gives a workshop a useful baseline for checking the vehicle. If the car has an aftermarket TCU calibration, engine tuning or previous transmission work, document that before disconnecting anything. Returning a modified vehicle to service may require additional planning beyond the physical installation.
High-value Mitsubishi parts often look similar across different model years, revisions and drivetrain combinations. That does not make them interchangeable. A later revision may use different calibration, sensors, gear ratios, brackets, connectors, valve hardware or emissions equipment. A part may also fit physically while creating a problem after installation. The safest workflow is to collect the VIN, the original part number, a photo of the installed label and a clear list of the vehicle modifications before comparing options.
For a workshop, this check protects labour time. For a private owner, it protects the budget. If there is any uncertainty, pause before buying and ask for a fitment check. This is particularly important for Evo driveline parts, engines and performance intake systems, where a small difference in configuration can affect the result far more than the product title suggests.
Good preparation prevents the usual post-installation arguments: a warning light caused by an untransferred sensor, a vibration caused by an old mount, a fluid leak from a reused seal or a performance complaint caused by an unrelated fault. Photograph the original installation before removal, label connectors and keep the old part available until the replacement has been confirmed. If the job involves software, transmission control, fuel, air metering or a major drivetrain assembly, plan the diagnostic and adaptation work before the vehicle is dismantled.
Compare the complete cost of ownership, not just the listed component price. A lower-priced assembly that needs unknown sensors, calibration, tyres, fluids, gaskets, labour or correction work can cost more than a properly identified part with the correct supporting hardware. For used components, condition evidence is essential. For new OEM components, availability and part-number revision should be confirmed. For performance parts, the exact vehicle application and the rest of the build must be considered.
Use this sequence: identify the vehicle; record its existing part number; confirm the target part; inspect what is included; plan consumables and programming; then arrange installation. It sounds basic, but it is the difference between a controlled repair and an expensive trial-and-error exercise.
A major component should be treated as a repair project, not as a single box arriving at the workshop. Before ordering, write down the vehicle identification number, model year, transmission type, engine code, current modifications, warning lights and diagnostic codes. The same model can have different original equipment depending on market, production period and specification. A clear list lets a seller or technician compare the request with the product reference instead of relying on a short description. It also creates a useful record if the work changes hands between a parts supplier, installer and tuning specialist.
Next, define the job boundary. Decide which related parts will be inspected and which will be renewed if their condition is uncertain. On an older performance car, seals, mounts, hoses, connectors and wear items can be just as important as the main assembly. Reusing every surrounding part may look economical at the checkout, but it can turn a successful installation into another removal job. There is no rule that every adjacent part must be replaced; the sensible approach is to inspect it with the assembly removed and make a documented decision based on condition, access and the planned use of the vehicle.
Documentation matters particularly when the vehicle is modified. Record the engine calibration, transmission calibration where relevant, intake and exhaust changes, turbo or fuel-system work, clutch specification and any prior repairs. These details do not automatically make a product unsuitable, but they affect how an installer should prepare the vehicle and validate it afterward. Do not assume that an existing tune, control module or sensor arrangement will remain correct after a major mechanical change. The workshop should have access to suitable diagnostic equipment and should verify the result before the car is put under full load.
For delivery planning, check the product page and confirm the condition of the packaging at arrival. Photograph the carton or crate before opening if there is exterior damage. Compare the identification on the received component with the order paperwork before installation, not once the original unit has already been removed. Set aside all supplied hardware and make an inventory. If the product is a long block, transmission or other assembly, clarify what is intentionally not included so the missing external parts can be transferred or sourced without delaying the job.
During installation, careful process control is more valuable than rushing. Keep fasteners, brackets and electrical connectors organised; take photos of routing and orientation; protect open lines and ports from contamination; and follow the vehicle-specific service information for torque, fluid, bleeding, relearn and initial start-up procedures. A new component does not correct a separate fault in the cooling system, charging system, fuel system or wiring. Basic checks before first start or first drive should include fluid levels, leaks, battery voltage, correct connector engagement and diagnostic scanning.
After installation, use a staged handover. Begin with a visual inspection and stationary checks, then complete the prescribed adaptation or calibration where applicable. Start with a gentle road test while monitoring warnings, shift or drivability quality, temperatures and leaks. Recheck fluid levels only by the correct procedure. Avoid treating the first drive as a performance test. The purpose is to confirm that the assembly and the vehicle systems work together before normal use resumes. Keep the order reference, pre-installation photos, diagnostic report and invoices in the vehicle file; they are useful for warranty conversations, future servicing and resale.
The same discipline helps when buying a performance intake. A claimed horsepower gain does not remove the need to confirm intake routing, filtration position, sensor placement, clamp security and compatibility with the rest of the build. An intake is part of the engine's air-measurement system, so an incorrect application or poor installation can create driveability issues that are mistakenly blamed on the product itself. With any high-value Mitsubishi part, an accurate specification, a complete installation plan and a documented final check are the practical way to protect the investment.
These articles form a practical Mitsubishi performance and drivetrain cluster. Use them when the repair or build overlaps with another major component:
The corresponding products can also be reviewed directly:
Contact the seller with your VIN and current part number if the listing is for a transmission, engine or model-specific performance component. Ask which components are included, whether the item is a complete replacement or a base assembly, and whether additional programming, sensors or hardware are required. A clear pre-purchase question is much easier than correcting an incorrect installation afterwards.
No. It is associated with the 2011–2015 Evolution X MR SST application. A GSR manual Evo X uses a different drivetrain, and earlier SST years require their own part-number check.
The supplied reference lists transmission code W6DGA-4-11A and TCM software part number 8631A971. Verify these details against the vehicle before ordering.
Yes. Fluid condition, electrical faults, sensors, battery voltage, wiring and calibration can all affect SST behaviour. Diagnose the vehicle before condemning the complete unit.
The exact work depends on the vehicle and installed configuration. A specialist should scan the car, check fault codes and complete any required adaptation or calibration procedures.
Send the VIN, vehicle year, MR or GSR specification, the original transmission part number and clear photos of the existing unit label.
2500A343 is a serious OEM drivetrain purchase, not a generic Evo upgrade part. Match it to a 2011–2015 Evo X MR SST by VIN and original identification, diagnose the root cause first and plan the installation, fluid service and electronic checks as one job. That approach protects both the vehicle and the investment.
Browse the Mitsubishi parts catalogue for related components, and use the exact product page as the reference point when requesting fitment confirmation.
Jul 21, 2026 by Edas Petrauskas
Jul 21, 2026 by Edas Petrauskas
