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High revs but no speed increase on auto kickdown!


RedM

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so do you get this problem all the time now then mate?

 

Not all the time. I think it's okay during normal driving but when putting a lot of power through it suddenly it slips like a mofo.

 

If I accelerate steadily then it'll go all the way through the gears to as fast as I dare. If I plant it and a lot of torque goes through the box that's when the slippage occurs.

 

TBH, it's been getting worse and worse since last spring. I thought it was turbo lag and me generally being more adventurous after my first winter in a Supra. I now can't remember what it was like before and I'm excited to find out.

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  • 3 weeks later...

After reading this thread, Ive considering the following:

 

Surely the best way to test for slip on an autobox would to be put the box in manual select 1st or 2nd gear and then just floor it. If revs shoot off without speed rising in this condition, then obviously your box is on the way out. If it doesnt, then everything should be OK?

 

I remember with manual cars, the best way to check for clutch slip would be to put the car in 3rd and then floor it from a rolling start.....

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I'm sure this has been answered but I'm damned if I can find an answer.

If I need to boot it whilst doing motorway speeds the autobox changes down and I get a lot of revs, the back end squats but it seems to take forever to gain speed. Today I pulled out to overtake and the car just kinda sat there revving it's nuts off before seeming to realise that I wanted to go fast and she then took off.

What's that all about?

 

 

To get this post back on line.

Mine does exactly the same as you described,can be quite embarrasing when someone is about to pass you and you floor the pedal - only to get a lot of noise with very little responce.

However I dont think it is anything to do with Turbo lag or the BOV as mine is an NA Auto.

Just hope its not the box though.

Cheers

Ian

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To get this post back on line.

Mine does exactly the same as you described,can be quite embarrasing when someone is about to pass you and you floor the pedal - only to get a lot of noise with very little responce.

However I dont think it is anything to do with Turbo lag or the BOV as mine is an NA Auto.

Just hope its not the box though.

Cheers

Ian

 

Based on my own experience I feel it might be the box. It's an old car. The box won't last forever no matter how 'bulletproof' people say it is.

 

I reckon the next couple of years will see more and more occurrences of this problem. Of course, I can then make a killing with my refurbed box.;)

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This kinda thing has happened once to me, the revs went up, but the car didn't pull like it normally does, then the box changed up, then I took off !. It hasn't happened since, but I think i'll get the fluid checked when the car's at Phoenix.

 

P.s. Well done mods for getting rid of the idiot poster in this thread. :)

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That's how it happened for me. Did it once then didn't do it again for months. Then it started to happen more and more frequently until it has wound up needing to be replaced.

 

Fresh fluid didn't work either.

 

I'll defo get Mark to check it over then, i've got a cooler to go on it, but that won't help if its already on its way out, and it won't last long after the single goes on. :rolleyes: :(

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  • 1 month later...
Guest sindrejl

Just happened to me too.. never seen it before until I was supposed to sell the car and the "buyer" was trying the car. After that it happends everytime I try to reconstruct it. Floor it with kickdown, then release the throttle a little, then give it alot of throttle again. The revs shoooots up straight to 7000rpm and the car crawls slowly forwards.. Only happends around 60mph and there is NO slippage at low speeds in manu mode. (only thing that happends if I try to check for slippage is huge amounts of burned rubber :p )

 

So.. is it the torque converter, fluids, electrical error or vsv? Also found this error it could be:

 

"Stator Clutch Breakage: A very abrupt application of power can cause shock loading to the stator clutch, resulting in breakage. When this occurs, the stator will freely counter-rotate the pump and almost no power transmission will take place. In an automobile, the effect is similar to a severe case of transmission slippage and the vehicle is all but incapable of moving under its own power."

 

So would that mean a replacement of the Torque converter? Anyone who can really explain this? With so many people with the same problem someone must've fixed this?

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I doubt in my case its the autobox, as ive just run a 14 second 1/4 mile consistently for 3 runs whilst at Shakespeare County Raceway last week. Id say in my case its a wonky VSV :)

 

Well done....

 

buuuutttt, I can go from a standstill, smoothly up through the gears and suffer no problems. On kickdown though it's a different matter.

 

I definitely have a knackered box and, yes, they do get worse over time.

 

I showed my mechanic all the VSV stuff and just like CW he insisted it's the box.

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No launch on my runs, but it was hard foot to the floor stuff from a standing start. If autobox was dodgy surely the extremes on the drag strip would have finished it off :)

14 second 1/4 for a stock auto which is 14 years old and with 120k miles on the clock aint bad :)

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No launch on my runs, but it was hard foot to the floor stuff from a standing start. If autobox was dodgy surely the extremes on the drag strip would have finished it off :)

14 second 1/4 for a stock auto which is 14 years old and with 120k miles on the clock aint bad :)

 

I'm probably wrong but I don't think the box is under the max torque loads when moving off, even if it is a hard standing start.

 

When my new box is fitted I'll either have been right or I'll have been wrong. If I'm wrong then my faith in mechanics/tuners will be zero.

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  • 5 weeks later...
For anyone still in the least bit interested the car goes in on Thursday for the box swap. I'll hopefully have some good news to report on Saturday when I pick it up.

:D Of course we are interested Martin. We like Supras, we like reading about problems and fixes, and we like you too.

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