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Transmission

Automatic transmission slippage

2006–2014 Mitsubishi Pajero 2.5 L diesel · U080

Diagnose and remedy automatic transmission slippage by inspecting and replacing the transmission fluid and filter, and checking the transmission control module for faults.

Difficulty
Garage job
Time
1h 30m
Parts
3
Sources
6

Before you start

  • Transmission fluid is hot after operation – wear heat‑resistant gloves to avoid burns.
  • Improperly supported vehicle can collapse – always use jack stands or a lift and verify stability before working underneath.
  • Running the engine with low or no transmission fluid can cause catastrophic gearbox damage.
  • Disconnecting the battery may reset electronic modules; be prepared to re‑learn shift patterns if required.
  • Incorrect fluid type or level will lead to further slippage or gear damage.

Steps

  1. Secure the vehicle Park on a level surface, engage the parking brake, place wheel chocks, and disconnect the negative battery terminal.
  2. Lift the vehicle Raise the front of the Pajero with a jack and support it on jack stands, ensuring the vehicle is stable before crawling underneath.
  3. Locate transmission fluid access points Find the transmission dipstick/fill plug (usually on the driver’s side of the transmission housing) and the drain plug at the bottom of the pan.
  4. Check fluid condition With the engine warm, remove the dipstick, wipe clean, re‑insert, then withdraw again. Note the level and inspect the fluid – it should be clear‑red and free of metal particles. Dark, burnt‑smelling fluid indicates the need for a change.
  5. Drain the transmission fluid Place a drain pan beneath the drain plug, remove the plug with the appropriate socket, and allow the fluid to fully drain. Replace the plug only after the filter is changed.
  6. Remove the transmission pan Unscrew the pan bolts in a criss‑cross pattern, carefully lower the pan, and set it aside. Be prepared for a small amount of residual fluid.
  7. Replace the transmission filter Locate the filter inside the pan, remove the retaining clip or bolts, pull the old filter out, and install the new filter ensuring it sits flush and the orientation matches the OEM design.
  8. Clean the pan and install new gasket Scrape away old gasket material, clean the mating surfaces, and place a new gasket (if required) onto the pan.
  9. Reinstall the transmission pan Bolt the pan back to the housing in the reverse order of removal. Torque the bolts to the specification listed in the service manual (verify before tightening).
  10. Refill transmission with correct fluid Using a fluid pump or funnel, add the specified Mitsubishi ATF (0W‑20 API SN) until the dipstick indicates the proper level with the engine idling in park.
  11. Reconnect battery and verify operation Re‑attach the negative battery terminal, start the engine, let it reach operating temperature, and shift through all gears while stationary to confirm smooth engagement.
  12. Scan the Transmission Control Module (TCM) Connect an OBD‑II scanner capable of Mitsubishi TCM diagnostics, read any stored codes, and address any faults (e.g., sensor or wiring issues). Clear codes after repairs.
  13. Road test Drive the vehicle, accelerating through the RPM range, and listen for abnormal noises or delayed shifts. Re‑check fluid level after the test and adjust if necessary.

Parts

  • Transmission fluid — Mitsubishi ATF, 0W‑20 API SN (or fluid meeting Mitsubishi 8‑speed automatic spec) ×≈9 L
  • Transmission filter — Mitsubishi automatic transmission filter for 8‑speed diesel ×1
  • Pan gasket (if applicable) — OEM gasket for transmission pan ×1

Tools

  • Jack and jack stands or lift
  • Wheel chocks
  • Socket set (including 13 mm and 17 mm)
  • Torque wrench
  • Fluid drain pan
  • Transmission fluid pump or funnel
  • Screwdrivers (flat and Phillips)
  • Trim removal tools
  • OBD‑II scanner capable of reading Mitsubishi TCM codes

Sources

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