V5A51 Transmission Master Rebuild Kit Mitsubishi Montero

Complete master overhaul kit for the Mitsubishi V4A51 / R4A51 / V5A51 / R5A51 four- and five-speed automatics - the rear-wheel-drive units behind the 2.4L through 3.5L engines in Montero Sport, Montero XLS, Pajero and Pajero Sport, L200, Triton, Strada, Challenger, and G Wagon. The kit covers a full teardown: friction plates, steel plates, the complete gasket and rubber seal set, metal-clad seals, sealing rings, and O-rings. Verify your case tag or valve body casting against the V4A51 / R4A51 / V5A51 / R5A51 part numbers before ordering, since the 4-speed and 5-speed versions share a family but not every clutch pack count.

These units usually come in on a burned direct or overdrive pack, a delayed or missing 3-4 shift, or a slipping reverse after the seals harden and start bypassing line pressure. Once the case is split, the pump seal, the drum piston lip seals, and the Teflon sealing rings on the input and output shafts are the parts doing the actual damage - they let apply pressure leak past instead of clamping the pack, and the clutches cook. Replacing them piecemeal is how a unit comes back a second time.

On the bench: air-check every drum after you stack it, set your clutch pack clearances with the selective plates before the case goes back together, and replace the filter and fluid at the same time. The kit is designed to be installed by a shop with the proper spring compressors and a clean bench - the friction plates should be soaked in fresh ATF before assembly. Buy the whole kit rather than chasing individual seals; the labor to go back in for one hardened lip seal costs more than the kit.