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The mkiv Supra Owners Club

AT Gearbox Problems !


Peter10654
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Hi Guys,

 

maybe someone has an idea.

 

I start the car and everything runs perfect but hear a loud noise from the AT. Put the Stick to "D" and car starts driving. I drive 50seconds and after that short period I can rev up to 6000 rpm and nothing goes forward, even if the Stick is in D.

 

Turn off the car and wait 5 Min. Start again and can drive 50sec. again, but only 50sec and the some error appears.

 

We changed the gearboxfilter and the oil. Nothing happens. Same errors.

 

So long as the loud noise appears, the AT shifts and go forward. The noise stops and the AT does nothing.

 

Any ideas ??

 

Oil (Dextron 3), Gearbox, Torque Converter etc. ??

 

Thanks

 

Peter

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Check for stored error codes, I suspect you may have a code 42.

 

I had a similar problem and it turned out to be the speed signal going corrupt in the odo.

 

There is a documented trick on here to sort the problem - by Emin I think (I would find it for you but works server is not playing ball).

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I use an AEM EMS and the whole last year everything was fine. I can believe it is an electrical problem because the car go forward but only few seconds and after this period no shifting and no lock up.

 

NOTHING. Seems I'm in the "N" position but I'm in "D" or "R, 2, L".

 

Is it possible to read out the errors also with the AEM EMS? I can believe it's the EMS because this error comes over longer time. First sympthom was it was driving like a high stall but only sometimes but now is everythin worn.

 

If you find something later if the server was OK, please let me know.

 

Thanks

 

Peter

 

Check for stored error codes, I suspect you may have a code 42.

 

I had a similar problem and it turned out to be the speed signal going corrupt in the odo.

 

There is a documented trick on here to sort the problem - by Emin I think (I would find it for you but works server is not playing ball).

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hi mate, im having the same problems with my reverse gear and im using the AEM, it will reverse for 20 seconds then just rev. I would get a AEM mapper to have a look, or try sending your map to one.

 

Interessting...

 

Myone run last year with the same setup perfectly. Could it be that a worn battery make something wrong with the AEM setup ?

 

What did you do ?? New mapping ??

 

Thanks

 

Peter

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First off, who mapped your car?

 

Has the AEM been installed with control of the autobox or has the stock ECU been left in place?

 

Are you able to upload your AEM calibration file for us to have a look.

 

If you havent got the software you will need to visit http://forum.aempower.com/forum/ to download it. You will also need a serial cable to connect to the ECU.

 

Once you are connected to the ECU you will also be able to datalog lots of info.

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Hi Wez,

 

thanks for your help.

 

Dimitri (the mad greek :)) mapped the car.

 

We don't leave the stock ECU into the car. Put out the original and put in the AEM. Dimitri mapped also the shift pattern into the AEM and we do a lot of test drive to adjust the pressures to shift faster or slower.

 

That's no problem to connect the Notebook to the car. I will go later afternoon to the car and can do this. What do you need ?

 

I called Dimtri @ the moment and he told me I should drive the short period it goes forward and go to the AT setup Menu and check if the speed sensor shows anything. I will try this.

 

What do you need ?? A log during driving the 50Sec or still any log reving in "D" position ?

 

Thanks and cheers

 

Peter

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There is some info on the AEM forum regarding the speed input, autos have two, as Dimitri said, hook up the laptop and monitor the speed to see if it displays the correct value.

 

You can also datalog this information and send it to Dimitri.

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I can't get this fluid. I called the local Toyota Dealer and he has done a look into his Paperwork and told me that Dextron 2 is the equivalent to the Toyota Fluid.

 

Ok ... I have now Dextron III but someone (i don't know i can trust him) told the Dextron III have the same specifications like Dex 2 with some new better things. (sorry i don't know what kind of it)

 

@ Wez

 

I will check it and give new Infos later.

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I thought the same Alex so could be the root cause, although I didn't think it would have such bad results.

 

Peter - Could you not get Nic on here to supply you with a few bottles of the Toyota Type T-IV fluid?

 

Cheers,

 

Brian.

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I doubt its the fluid......aren't you running silly power in your car?? is it a BL transmission or stock?

 

Peter - Could you not get Nic on here to supply you with a few bottles of the Toyota Type T-IV fluid?

 

I did this with mine and it didnt make much difference to be honest

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The reason I don't think its the oil or something electrical is the loud noise into the gearbox during idle. It sounds scratching or something like this.

 

If the loud noise ends the AT doesn't work. So long the sound appears everything runs but only the told 50sec.

 

I will check tomorrow speed signals and after that we will go to the next step.

 

Is is possible there is something worn into the gearbox ? TC or Oilpump ?

 

I dive a GT40 Single Setup with stock At. Maybe its time for rebuild oder BL Tranny.

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Only 1.2 bar... I know it's a little bit risky but another guys did the same. I never drove very hard with the car. No Quatermile no races anything. I drive just some high speed pulls on german Autobahn.

 

I would class that as hard driving........with out meaning to sound like a defeatest, it sounds like your box is fecked:(

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Of course you are in right also.

 

I have a Jspec AT Gearbox and an used TC in spare. I think after i have checked any speed signal problems I will change the TC and the Gearbox to test. If this was the reason, I decide to buy a BL Tranny or sell the car and buy an 6-Speed.

 

BTW: Anybody knows what to change, if I change my UK Spec AT to an Jspec AT ? I think there are differences because the UK unit is an A340E and the Jspec is an A340 !!

 

Peter

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Update:

 

I have tried the change the gearbox but I think I have a wrong spare unit maybe from another car.

 

Can somebody tell me if this Number 16 Gearbox is from a J-Spec Supra. I thought I need to change only the connection from the Gearbox to the cardan shaft but that's not possible because the shaft into the gearbox is longer and different.

 

These are the pictures from the worn UK Spec Gearbox and form my spare one. Different numbers on the gearbox. Uk Unit "22" and Spare Unit "16" also the badge is different.

 

Please take a look to the pictures.

 

UK Spec

http://img2.putfile.com/thumb/5/14803561817.jpg

 

http://img2.putfile.com/thumb/5/14803562348.jpg

 

http://img2.putfile.com/thumb/5/14803562386.jpg

 

 

Spare Unit (maybe Jspec ?)

http://img2.putfile.com/thumb/5/14803562341.jpg

 

http://img2.putfile.com/thumb/5/14803562340.jpg

 

http://img2.putfile.com/thumb/5/14803562359.jpg

 

Thanks

 

Peter

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stock autobox cant cope with more than 450+ bhp...

 

 

Maybe... But I need to fix it quick and cheap and I think I don't have more than 500bhp with only 1.2 bar. Most time only 1.1bar

 

EDIT:

 

Could it be that this spare unit is from an NA Supra ??

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Update:

 

I have tried the change the gearbox but I think I have a wrong spare unit maybe from another car.

 

Can somebody tell me if this Number 16 Gearbox is from a J-Spec Supra. I thought I need to change only the connection from the Gearbox to the cardan shaft but that's not possible because the shaft into the gearbox is longer and different.

 

These are the pictures from the worn UK Spec Gearbox and form my spare one. Different numbers on the gearbox. Uk Unit "22" and Spare Unit "16" also the badge is different.

 

 

Thanks

 

Peter

 

If I remember correctly you just need to change that output shaft. Even Boostlogic is buying JDM Aristo tranny cores to upgrades, they just change the output on them.

 

http://www.supraforums.com/forum/showthread.php?t=422628

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