Hi everyone please could i have some help my 1995 4.0 p38 it has a strange tramission problem. my symtoms are no drive in reverse or drive but when i rev hard its trys to move but just dont seem to have enough friction . all the gear select ok and all apear on dash display in correct order and i have no gearbox fault message. the only way it will drive is if i select drive or 1 2 3 and rev hard then it clunks and i have drive but it doesnt change out of that gear and then it will display gearbox fault.. ih a ve changed the fluid .on trying again same symtoms select any gear and no drive only slight move ment with no fault on dash then rev hard and clunk i have drive with gearbox fault on display ? Any help would be great
jamesmartin
Well-Known Member
what was oil like you changed ?
jamesmartin
Well-Known Member
brownish is just old oil ,blackish would have indicate burnt clutch pack ,sounds like low pressure or sticky valve ,oil level correct .clean filter with o rings fitted ?
Ive just replaced the oil as i thought might be a quick fix . i will buy a filter and try that ! When you say sticky valve and low pressure how can i check this ? Is there any procedure? Would low pressure be caused by a clogged filter ? Is that why it engages into drive when reved hard ? Thanks for your reply i have been banging my head over this .
jamesmartin
Well-Known Member
pump is driven from torque convertor so the higher the revs the more oil pumped ,filter is on pump pick up ,pressure would need a guage ,your clonking would seem like valve sticking then moving as pressure built perhaps ,could also be free wheel clutch not locking then doing so but usually it causes delay or total loss had you had any noise prior to fault
Just to ad when i rev it in d or 3 2 1 it will slip there will not be any fault message so i will blip the throttle upto 5k and it will clonk and then drive in 3 it seems with gearbox fault on dash briefly and then the display goes blank leaving mileage but no gear position. i can now drive and stop and pull away again with no slipping but it only stays in that gear also i can shift between high and low . when i turn of and restart the gear fault has gone and all my gears select fine on dash but slipping has come back?
With gearbox oil cold dip box. Fluid should be well up above full mark. Start engine and dip again. If level has dropped to full mark. Pump is working and filling torque convertor. In D first gear clutches 4 a 11 should be engaged. Clutch 4 is engaged manually when you select D, clutch 11 is selected electronically. If you have no gearbox fault would think you have a very sticky valve block. Or a very clogged filter. Was it ok before you changed oil? Do not rev engine to 5k if you get a sudden engagement you will snap something.
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Only certain way is to strip and clean valve block. But that is NOT something you want to be doing unless you have a service sheet for it and REALLY know what you are doing. You could try a bottle or two of Lucas transmission fix.
StuckAgainSteve
Well-Known Member
Well that isn't the correct way for starters.
If oil level was correct when drained you should have got around five litres out of it. Refill with 4.5 litres then with engine running and after moving stick through the gears dip and slow fill until full mark is reached. Or fill until it runs out of filler/level plug if you don't have a dip stick. Then start engine go through gears and fill until it runs out again.
Torx loc screws holding filter can be a bastard to get out. Make sure you have some good bits.
jamesmartin
Well-Known Member
t 27 torx bit give screw head a tap if tight
