auto box problem

[toy231]

HELP. i have an intermittant problem on my 1994 3.0ltr auto. sometimes it wont go up into top gear and you have to rev it higher to make it go up through the other gears. all electrical connections were clean by a specialist g/box garage and it worked fine for 10 days untill the same problem returned. i took it back, they again cleaned everything but cannot actually find a problem. it is ok now but i think it still takes too long before changing up? is it something to do with a throttle positioning sensor ????? and what is one of those?

[BUSHWHACKER]

Erm, You have'nt got the ECT button pressed in have you?

[toy231]

Erm, You have'nt got the ECT button pressed in have you?

unfortunately no. all switches are where they should be.
although the box is working there does not seem to be a clear change of gears up through the box. 1st to 2nd is good but the next 2 changes seem to slip together. almost like one of those strange gearboxes in some of those small volvo's that work on a cone system. sorry but difficult to explain. more suggestions welcome.

[andy]

You will get variable revs until the gearbox locks up at 55mph.

[BUSHWHACKER]

Is your transmission fluid at the correct level? and is it a nice red colour and not brown?

[toy231]

Is your transmission fluid at the correct level? and is it a nice red colour and not brown?

yes affraid so. i checked oil before i took it to g/box garage and it was fine and the garage has dropped the sump and re-filled with new oil. twice.

[BUSHWHACKER]

The only other thing I can think of, is a torque converter problem.

[Rob]

From what I've read in the past, there's several solenoids that control the shifts. These can get sticky / slow moving / jammed / lazy. Often not too much of a job to replace as I understand most of them are accessible from the bottom when the sump is off. Might be worth enquiring about at the transmission place.

[toy231]

solenoids

From what I've read in the past, there's several solenoids that control the shifts. These can get sticky / slow moving / jammed / lazy. Often not too much of a job to replace as I understand most of them are accessible from the bottom when the sump is off. Might be worth enquiring about at the transmission place.

thankyou for your reply, i am going to try to sort this one out myself, its become a bit of a challenge. is removing the sump much of a problem? would the solenoids be obvious to a novice. would it just be a question of cleaning them and/or how can i check if they are faulty. could it perhaps be a problem with a speed sensor?

[Uplander]

thankyou for your reply, i am going to try to sort this one out myself, its become a bit of a challenge. is removing the sump much of a problem? would the solenoids be obvious to a novice. would it just be a question of cleaning them and/or how can i check if they are faulty. could it perhaps be a problem with a speed sensor?

notwithstanding the above suggestions, how about checking whilst driving along about 1500 to 2000 revs about 40 to 50 mph, and switchin IN then OUT the overdrive button, any change to gears, about this range there should a noticeable difference...changing into /out of top gear f'rinstance: if not, i'll go back to sleep, whilst you persue other angles.....

[toy231]

o/d in or out

notwithstanding the above suggestions, how about checking whilst driving along about 1500 to 2000 revs about 40 to 50 mph, and switchin IN then OUT the overdrive button, any change to gears, about this range there should a noticeable difference...changing into /out of top gear f'rinstance: if not, i'll go back to sleep, whilst you persue other angles.....

tried that one. o/d is not engaging so no difference to revs.
KEEP THEM COMING !!

[The Mighty WAH]

Overdrive engagement speed

A couple of things that may, or may not, be relevant. Have a 93 3.0 TD auto, so the same model.
The engagement of my overdive seems to be engine temperature sensitive. Not sure if it is meant to be like this but it is consistant in how it acts.
Whilst warming up the overdrive will not engage until the engine temperature needle has reached the exact normal running position. Should this go above this level it also will not engage. Had this situation a couple of weeks ago when towing the caravan. It was fairly hot and I was climbing some long hills between at 65-70mph. The overdive normally engages around 55-60mph, depending upon throttle position. It would not engage even when up to 70mph, so eased back until the temperature returned to the normal position and then the overdive engaged as per normal. I have had this situation before but did not notice the correlation with the temperature. Not sure if this a design function or just how mine works?

Colin

[toy231]

A couple of things that may, or may not, be relevant. Have a 93 3.0 TD auto, so the same model.
The engagement of my overdive seems to be engine temperature sensitive. Not sure if it is meant to be like this but it is consistant in how it acts.
Whilst warming up the overdrive will not engage until the engine temperature needle has reached the exact normal running position. Should this go above this level it also will not engage. Had this situation a couple of weeks ago when towing the caravan. It was fairly hot and I was climbing some long hills between at 65-70mph. The overdive normally engages around 55-60mph, depending upon throttle position. It would not engage even when up to 70mph, so eased back until the temperature returned to the normal position and then the overdive engaged as per normal. I have had this situation before but did not notice the correlation with the temperature. Not sure if this a design function or just how mine works?

Colin

thanks for your reply. i will check the temp. sensor. you say yout o/d engaged at about 55mph, i stand to be corrected but o/d should engage long befor that. i think what you are talking about is what they call 'gearbox lock-up' which locks the rear diff to the torque converter which acts like another gear by dropping the revs. thanks anyway.