RE4R01A Transmission Master Rebuild Kit, Nissan Pathfinder

The RE4R01A (also stamped R4A-EL) is the four-speed longitudinal automatic Nissan bolted behind the Pathfinder, and after enough miles the frictions glaze and the rubber hardens. You feel it as a soft or slipping shift, a flare between gears, or a delayed engagement when you drop it into drive on a cold morning. Once a transmission is doing that, no additive fixes it — the clutch material and the seals are worn out and the unit has to come apart. This is the box of parts that goes back in when it does.

It is a master overhaul kit: the friction clutch plates, the paper and rubber gaskets, the metal-clad and lip seals, the sealing rings and the O-rings needed to reseal and re-clutch the RE4R01A in one rebuild. It replaces OE part numbers B075820A, B075880A and W075881A. Fitment is the Nissan Pathfinder running the RE4R01A / R4A-EL — confirm the model number cast into your case before you order, because Nissan ran several similar RWD four-speeds and the frictions are not interchangeable between them.

On the bench the sequence is the usual one: tear the unit down, wash and inspect the drums, hard parts and pump, then reassemble with every friction, gasket and seal in this kit soaked and set to spec. Because it carries the soft parts and clutches rather than the drums and shafts, it is the right kit for a transmission whose hard parts checked out and just needs to be resealed and re-clutched. If a drum or the pump is scored, source that hard part separately — this kit covers everything that wears out on a normal high-mileage rebuild. Manufacturer part number BL-10035221, shipping weight 8.8 lb. Ships from the USA.