This LRO reader emailed LRO.firstname.lastname@example.org to ask Julian Gilling about Range Rover P38 gearbox woes.
The pipe to the gearbox oil cooler burst on my 1997 P38. I replaced the cooler and both pipes to the cooler directly to the gearbox. I filled it up with Dexron II and III oil as Halfords ran out of D2. When I started it up I had no forward gears working, only reverse.
Can you help?
If your P38 was driven any distance after losing the cooler pipe, there’s a chance the clutch pack has been damaged – that wouldn’t affect reverse. Hopefully, though, it’s simply a blockage, or an air lock in the pump or valve block. The difference in fluid between Dexron II and III shouldn’t cause drive loss, initially after a refill, but your box should ultimately be filled with ATF Dexron III. P38s from the 1999 model-year onwards have a definitive fill procedure, which I adapt slightly to suit earlier models as it helps to clear air locks.
I fill the box to the minimum required, and (without actually trying to travel) start the engine and run the gear selector through
all of the gears then, with the engine still running and the transmission in Park, fill to the normal level. If the issue isn’t just an airlock, you may need to ask an auto gearbox specialist to have a look. Due to the loss of fluid, maybe the filter has picked up some residue from the bottom of the box, and is restricting oil flow, which could cause similar symptoms.
If it is that, dropping the gearbox sump and changing the filter should cure it.
This workshop advice appeared in the August 2015 issue of LRO. Back issues are available to download on digital devices here.