Mk3 Supra Autobox Problems

[MattTodd]

Hi,

My mate Graham has a mk3 Supra. He's been after one for ages and picked this up about 3 months ago. Last night while driving, it effectively dropped into neutral and now you can't get any drive from it. It will select all gears with the shifter fine, but won't go anywhere it drive, simply revs up. Reverse works fine.

To me, this sounds like the forward clutch in the box has burnt out, I need to smell the ATF fluid to confirm. If there's any other things that might cause these symptoms, what might they be? Are there any electrical switches which give up and would prevent drive from being selected?

Worst case scenario and the box is toast, can anyone reccommend an automatic transmission specialist to rebuild the box? The car only has 114,000 on it, which to my mind is fairly low for an autobox to let go, so at this stage if the box has given up, I think he'd be better off getting his box rebuilt than dropping a 90,000 miler box in for it to go bang in 10,000 miles time.

The car is a 1989 G plate Supra 3.0i, it's the non-turbo, and a UK model.

Cheers,

Matt

[Karma Supra]

Firtst thing first, get under the car and check that the shifter mechanism is ok, it is adjustable and if it has slipped could give similar symptoms.

The auto boxes are strong and reliable, I have had cars that have drive auto supras with many more miles that have been fine!

I take it you have checked the fluid level too?

[MattTodd]

Firtst thing first, get under the car and check that the shifter mechanism is ok, it is adjustable and if it has slipped could give similar symptoms.

The auto boxes are strong and reliable, I have had cars that have drive auto supras with many more miles that have been fine!

I take it you have checked the fluid level too?

Hi, thanks for your reply, I really appreciate it. The car got trailered home in the dark last night, and he's at work today, so I'm going off what I saw last night and what he's told me.

I haven't smelt the fluid or checked the level. Apparently it does smell burnt, but I can't guarantee that as I haven't smelt it yet. I will tonight. Also the recovery / AA guy was going to try adding fluid, but couldn't work out where to add it. Apparently the recovery guy just tried revving it hard as well to see if it would "kick" into gear. If it'd been my car I would have hit the roof. I'll know more tonight, my checklist so far is to check the fluid level, and smell the fluid thus far.

All my car knowledge is Jags and Range Rover classics sadly, and I've never had gearbox troubles with either, could you give me a bit more information on what I'm looking for with regard to the shifter mechanism? I can back it up onto 2 ramps tonight and get underneath, would pictures help at all? I'll get a video tonight of exactly what it's doing as well, that maybe of some help.

Again, thanks for your reply.

EDIT :

Another question he'll ask me tonight, worst case scenario and we are looking at a gearbox rebuild, what's the procedure for removing the gearbox. I notice you converted yours from automatic to manual Karma Supra, do you need to pull the engine out with the box on the end, or can you get the box out with the engine is situ?

[Karma Supra]

The shift in the cabin simply operates an arm, the arm has a long slot machined into it, and a nut and bolt, you adjust it by losening off the bolt and sliding it along... it may not be the case, but its worth a try!

I used to top up the autos by filling using the dipstick tube.... easiest way! The AA man was clearly an idiot ;)

The gearbox can be pulled with the engine in situ. just dosconnect the shifter, prop, kickdown cable, dipstick and tranny cooler lines, undo the rear mount, lower the back the whole lot rocks back and undo the bell housing.. you'll need a decent 3/8" extension bar/wobber tip/UJ to undo the top two bolts.

There are plenty of auto cars being broken, the gearboxes are very cheap as in all honesty they very rarely fail. I have had one sitting in my shed for about 4 years that I have not got around to binning yet, I'd say you could have it, but the value of it is not even worth the fuel/time/courrier costs to get it to you!

Try www.mkiiisupra.net you might find a decent 'box nearer home !

[MattTodd]

The shift in the cabin simply operates an arm, the arm has a long slot machined into it, and a nut and bolt, you adjust it by losening off the bolt and sliding it along... it may not be the case, but its worth a try!

I used to top up the autos by filling using the dipstick tube.... easiest way! The AA man was clearly an idiot ;)

The gearbox can be pulled with the engine in situ. just dosconnect the shifter, prop, kickdown cable, dipstick and tranny cooler lines, undo the rear mount, lower the back the whole lot rocks back and undo the bell housing.. you'll need a decent 3/8" extension bar/wobber tip/UJ to undo the top two bolts.

There are plenty of auto cars being broken, the gearboxes are very cheap as in all honesty they very rarely fail. I have had one sitting in my shed for about 4 years that I have not got around to binning yet, I'd say you could have it, but the value of it is not even worth the fuel/time/courrier costs to get it to you!

Try www.mkiiisupra.net you might find a decent 'box nearer home !

Hi,

Unfortunately my camera was flat last night, so no pictures yet I'm afraid. The car creeps forward in drive today, and reverses fine, what we're going to do first is a full fluid change for the transmission.

Can I ask what transmission fluid is preferable, in the past I've used Castrol Dexron III ATF for my jags, but I'm aware some boxes may be particular, so it's worthwhile checking. Also, I forget from looking last night, is there a drain plug for the transmission, or do you need to remove the sump pan and drain the fluid that way whilst changing the filter and gasket.

How much fluid does the transmission hold? On jags you need to do about 3 full flushes to get a full change as obviously some fluid is still in the tranmission during draining etc.

Cheers,

Matt

[Karma Supra]

Dextron 3 will be fine. I think it holds about 4 litres... or just under. You can just drain it out.... although pulling the sump off with make sure you do a better change, I *think* there is a metal gause in there, you can just clean it and reuse.

I have fitted a few but never opened up an auto box so thats about as much as I know!

[MattTodd]

Dextron 3 will be fine. I think it holds about 4 litres... or just under. You can just drain it out.... although pulling the sump off with make sure you do a better change, I *think* there is a metal gause in there, you can just clean it and reuse.

I have fitted a few but never opened up an auto box so thats about as much as I know!

That's great, you've been really helpful, thankyou!

[MattTodd]

Hi,

bit of an update. I'll get some videos at lunchtime as I've brought my camera, but no joy. I've checked the gear linkage moves as it should, this morning I flushed 10 litres of fresh ATF through the transmission. 6 litres I guess, as I had 10 litres in total and the box is full now, but if it only holds 4.5, that's still a good thorough flush.

I did it buy putting the front of the car on axle stands to get the gearbox to drain to the back, removing the sump plug and draining the fluid to a bucket, I then topped it up with fresh fluid, started the car, changed through the gears slowly without applying revs, turning the car off, draining again and repeating.

After this sadly there's still no drive at all. Reverse works great, but no forward drive.

The old fluid is very black, and smells burnt to me.

What's next chaps, any suggestions? To my mind, the forward clutch must be shot in the box, in which case if I'm right it must be new box time?

Matt

[MattTodd]

also.... when it's cold, it will creep forward in drive, like 3 - 5 feet etc, but it you stop and put it in reverse, then go back to drive you get nothing again.