Mini1

Greetings All,
Strange one here, at least to me. My '92 V8 EB II Fairmont S/W has developed an annoying tendency of dropping into self protect/limp home/stuck in 3rd gear mode when slowing down and dropping from 2nd gear back to 1st. It will sometimes cause a slight bump which can be heard and felt as it goes into 1st, but more often than not nothing unusual happens to indicate a change of mode has occured. The car has been standing for about 6 months, engine out, torque converter out and gearbox suspended at a slight forward facing downward angle. The gearbox sump pan was removed, oil filter, pan gasket and oil renewed. My local transmission magicians have had the car on their diagnosis unit shortly after the second occurrance, when the battery required disconnecting for a period of time to effect a reset and return to normal operation mode. Their diagnosis was "valve pressure solonoid circuit", and 1 "undefined code", however, they were unable to duplicate the problem in order to confirm the diagnosis and effect a repair. Since they have returned the car, a simple shut off the ignition and restart has reset the 'box. The only "real" attempt to to sort the problem has been the disconnecting of all the electrical plugs and spraying out with contact cleaner to eliminate moisture. The vehicle battery has been renewed, the previous battery being 5+ years old (but still seemed OK).
Any thoughts would be welcomed, from sticking/u/s solonoids to insulation breakdown on the wiring. The car has 297,000 kilometers on the clock.
Cheers,
Rob.

 

Mini1

Greetings All,
Update time, the problem appears to have been overcome by adding a bottle of BTR ATF conversion formula from Lube Guard in the USA. Have no longer got the empty 5lt container of ATF used when re-filling the box, but must assume that Dexron was supplied not TQ 95 as requested. The oil was not Castrol, so it may be a cross reference cock-up - have to be more careful checking that the substitute part is suitable for the job.
Cheers,
Rob.

Mini1

Bugger, spoke too soon! The bloody thing has started playing up again! Have had the oil replaced and a replacement inhibitor switch fitted, since it now has decided that whatever range is selected on the gear lever ( 1,2,3 or D) it is going to drive in D and use the full range of gears until it decides to go to limp/self-protect mode. (This may have been the case in the past, but not really noticed by me or anybody else.) Nothing showing up on the diagnostic decoder, might need a second opinion there. Any suggestions would be greatly appreciated.
Rob.

Mini1

Still playing up even after a 2nd hand gearbox module and wiring loom were fitted. Since the problem mainly occurs on 2nd to 1st downshifts with maybe 2 occasions on 1st to 2nd upshifts, logic states that the solenoid responsible for these shifts is at fault. Still don't understand why the gear selector does not override the box.
My next step is to investigate the amount of work to swap the 92 EB box with something newer - what needs replacing between 6 cyl and V8 applications, sedan and wagon applications, the cost and the availability of good used parts in NZ.
Your comments and suggestions welcomed.
Cheers,
Rob.