Automatic Transmission not engaging

[admux]

Hi all,

I've bought a 94 mark IV Supra NA.... Its been given a good hammering by previous owners and still works but with a few problems..

The worst issue is that the transmission slips / not engages when under load (going up slopes) at low speeds

An example would be driving up a slope in a multi-story carpark, I have to go slow to avoid scraping the bottom of the body kit and exhaust on the speedbumps i'm in D (drive) and when I come off the gas and go back on the gas it disengages the gear and start rolling backwards, I have to brake and then gas up up again ....or let it roll back and wait for it to re-engage (no good when cars are behind you)....

I don't seem to have an issue on the flat....

Another (an probably related issue) is there seems to be no kickdown when you floor the gas pedal, it stay in the gear you are in and speeds up without dropping to a lower gear.

All this points to a tranny problem... I checked the tranny fluid and it looked ok (red and not burnt) but it was way overfilled, I pumped some out and it's at the correct level now...

any thoughts ? is a tranny re-build imminent ?


ta,

Addy

[pwpanas]

Originally Posted by admux

Hi all,

I've bought a 94 mark IV Supra NA.... Its been given a good hammering by previous owners and still works but with a few problems..

The worst issue is that the transmission slips / not engages when under load (going up slopes) at low speeds

An example would be driving up a slope in a multi-story carpark, I have to go slow to avoid scraping the bottom of the body kit and exhaust on the speedbumps i'm in D (drive) and when I come off the gas and go back on the gas it disengages the gear and start rolling backwards, I have to brake and then gas up up again ....or let it roll back and wait for it to re-engage (no good when cars are behind you)....

I don't seem to have an issue on the flat....

Another (an probably related issue) is there seems to be no kickdown when you floor the gas pedal, it stay in the gear you are in and speeds up without dropping to a lower gear.

All this points to a tranny problem... I checked the tranny fluid and it looked ok (red and not burnt) but it was way overfilled, I pumped some out and it's at the correct level now...

any thoughts ? is a tranny re-build imminent ?


ta,

Addy

I assume it's an automatic transmission? If so, I agree with you that a transmission rebuild is likely (probably bad sprag(s)). However, these transmissions are pretty rugged and typically don't go out unless the horsepower has been increased (eg. via nitrous oxide injection for an n/a). It may be cheaper for you to find another transmission in a junkyard, and it should work just fine.

I also agree with you that the kickdown problem is probably related too. However, that kickdown switch is a separate circuit and in theory it could have an electrical problem. The switch is under the carpeting, right under the accelerator pedal.

[admux]

quick update on this.... I topped up the tranny fluid, put about another 500ml in it and it's stopped slipping.

defo something wrong with the tranny but it behaves better when u overfill the fluid

next job is the manifold.... it has a hole so it's bit noisy !!! head turner though

[pwpanas]

Originally Posted by admux

quick update on this.... I topped up the tranny fluid, put about another 500ml in it and it's stopped slipping.

defo something wrong with the tranny but it behaves better when u overfill the fluid

next job is the manifold.... it has a hole so it's bit noisy !!! head turner though

Be careful. An overfull auto tranny can be a fire hazard. If it's driven hard, tranny fluid can splash from the overflow valve onto the exhaust.

[lawlerCoaster]

Originally Posted by admux

quick update on this.... I topped up the tranny fluid, put about another 500ml in it and it's stopped slipping. hid kits

defo something wrong with the tranny but it behaves better when u overfill the fluid

next job is the manifold.... it has a hole so it's bit noisy !!! head turner though

Post some pictures of your car! =)