Hey guys. I have been troubleshooting my transmission now for about a year. I am running out of ideas and patients. Currently what's happening, is that the torque converter, for no apparent reason is locking up in third gear. Also, sometimes under wide open throttle conditions, shifting between second and third gear causes the car to bounce off the rev limiter. Other times, shifting between second and third gear shifts normally.
The transmission two years ago was built by a high-performance transmission racing shop. It's rated for about 800 brake horsepower. It is controlled by a suprastick transmission computer.
The motor is a forged and built 7MGTE.
Any ideas would be helpful to make the torque converter not lock up in third gear. Or to understand why it is locking up. Also it would be good to understand why the transmission might slip in second of third-year transitions.
Below I'm copying and pasting a timeline that everything up about these issues since they started over two years ago. Be prepared for a long read, but I believe that all the information is useful in understanding what's going on for all you technical guys ready to help me out.
2010:
July: Increased horsepower from 300whp to 400whp.
September: Transmission within 2 months started to slip.
November: Brought to Russels to rebuild and improve transmission to withstand up to 500bhp. Installed raybestos blues, new parts, and 2700 stall torque converter.
December: Returned home
2011:
April – May drove car for season. Drove as if in break-in period for tranny.
June- Started to feel a loss of power and started to blow blue smoke.
July- Compression test said #1 cylinder failing
August – parked car for season.
2012:
February – brought to Ballistic for engine performance build and replace ecu with AEM standalone.
June – Car picked up for break in. Timing too advanced, can’t drive the car too far.
July – Car receives break-in tune by Granite State Dyno (GSD) & Tune. Car stalls randomly as it tries to climb over 3k rpm. Diagnosed as a tuning issue, shift point programmed where it isn’t suppose to be in AEM computer.
August – Car receives final tune. AEM does not communicate with the auto transmission computer nor the transmission. Torque converter constantly locks/unlocks at low speeds. Locks at highway speeds normally.
September – Ballistic sees that there is a way to communicate to torque converter by wiring the converter wire into the aem computer. GSD tunes the converter to lock up in 4th gear over 40mph.
October – I feel confident to start to push the car and try some standstill WOT pulls. 1st gear does not shift from 1st to second without redlining. 2nd into 3rd gear and 3rd into 4th perform fine. Torque converter performs fine all the time as programmed. Only issue is cannot drive car under WOT from 1st to 2nd gear.
November – Supra community recommends to me and Ballistic to use Suprastick. A computer designed for my generation supra. Says it should take care of shifting problems and torque converter problems.
Suprastick info is here: http://www.latentsolutions.com/suprastickuv.html
March – Suprastick is installed by Ballistic Motorsports. Driving with suprastick seems to work fine as before installed. Shifts more positive, and can be manually controlled by the steering wheel buttons.
April – After driving more frequently, find that the first to second gear shift still is not engaging, causing the car to rev too high. All other gears drive as did before, but more responsive. I try to adjust shift tables to cause 1st gear to shift earlier under WOT to prevent from over revving. This does not work.
May – I contact Russells about the shifting issues. They ask for me to make time to come down and troubleshoot. I go on my car cruise up 93 to Lincoln. Transmission doesn’t engage Reverse after long drive. I drive home and park the car. Russells is contacted for a dropoff date to resolve the Reverse issue.
June – Car is dropped off at Russels. Determined the transmission was overheated at some point, and clutches among other parts are damaged. Worn/damaged parts replaced under warranty.
July – Pick up car from Russels and drive for a period of time. First to second gear shift is now working for the first time since before the motor rebuild. Second to third shift now will over rev if done under more than 80% throttle. 3rd gear torque converter locks up under any throttle. All other gears work normally. Tory troubleshoots with suprastick computer and determins that the speed signal is inconsistent and may be causing some of the problems.
Mid July- Reprogram AEM computer speed signal for the 7mgte engine instead of generic speed sensor. Seems to improve speed readings at the suprastick computer at lower speeds.
Late in July – Meet with Russels to troubleshoot with Suprastick computer. Reprogrammed the computer shift tables to factory settings. Tory determines that the torque converter is locking up in 3rd gear. Tory programs computer to not allow converter to lock until 4th gear is engaged.
Current – torque converter is still locking up in 3rd gear under more than 40% throttle. Under some conditions, car will sometimes shift normally between 2nd and 3rd gear (auto mode), but other times may hit rev limiter (especially while in manual mode and the car is shifted later than 5500 rpms).
Thanks for any help in advance!
The transmission two years ago was built by a high-performance transmission racing shop. It's rated for about 800 brake horsepower. It is controlled by a suprastick transmission computer.
The motor is a forged and built 7MGTE.
Any ideas would be helpful to make the torque converter not lock up in third gear. Or to understand why it is locking up. Also it would be good to understand why the transmission might slip in second of third-year transitions.
Below I'm copying and pasting a timeline that everything up about these issues since they started over two years ago. Be prepared for a long read, but I believe that all the information is useful in understanding what's going on for all you technical guys ready to help me out.
2010:
July: Increased horsepower from 300whp to 400whp.
September: Transmission within 2 months started to slip.
November: Brought to Russels to rebuild and improve transmission to withstand up to 500bhp. Installed raybestos blues, new parts, and 2700 stall torque converter.
December: Returned home
2011:
April – May drove car for season. Drove as if in break-in period for tranny.
June- Started to feel a loss of power and started to blow blue smoke.
July- Compression test said #1 cylinder failing
August – parked car for season.
2012:
February – brought to Ballistic for engine performance build and replace ecu with AEM standalone.
June – Car picked up for break in. Timing too advanced, can’t drive the car too far.
July – Car receives break-in tune by Granite State Dyno (GSD) & Tune. Car stalls randomly as it tries to climb over 3k rpm. Diagnosed as a tuning issue, shift point programmed where it isn’t suppose to be in AEM computer.
August – Car receives final tune. AEM does not communicate with the auto transmission computer nor the transmission. Torque converter constantly locks/unlocks at low speeds. Locks at highway speeds normally.
September – Ballistic sees that there is a way to communicate to torque converter by wiring the converter wire into the aem computer. GSD tunes the converter to lock up in 4th gear over 40mph.
October – I feel confident to start to push the car and try some standstill WOT pulls. 1st gear does not shift from 1st to second without redlining. 2nd into 3rd gear and 3rd into 4th perform fine. Torque converter performs fine all the time as programmed. Only issue is cannot drive car under WOT from 1st to 2nd gear.
November – Supra community recommends to me and Ballistic to use Suprastick. A computer designed for my generation supra. Says it should take care of shifting problems and torque converter problems.
Suprastick info is here: http://www.latentsolutions.com/suprastickuv.html
March – Suprastick is installed by Ballistic Motorsports. Driving with suprastick seems to work fine as before installed. Shifts more positive, and can be manually controlled by the steering wheel buttons.
April – After driving more frequently, find that the first to second gear shift still is not engaging, causing the car to rev too high. All other gears drive as did before, but more responsive. I try to adjust shift tables to cause 1st gear to shift earlier under WOT to prevent from over revving. This does not work.
May – I contact Russells about the shifting issues. They ask for me to make time to come down and troubleshoot. I go on my car cruise up 93 to Lincoln. Transmission doesn’t engage Reverse after long drive. I drive home and park the car. Russells is contacted for a dropoff date to resolve the Reverse issue.
June – Car is dropped off at Russels. Determined the transmission was overheated at some point, and clutches among other parts are damaged. Worn/damaged parts replaced under warranty.
July – Pick up car from Russels and drive for a period of time. First to second gear shift is now working for the first time since before the motor rebuild. Second to third shift now will over rev if done under more than 80% throttle. 3rd gear torque converter locks up under any throttle. All other gears work normally. Tory troubleshoots with suprastick computer and determins that the speed signal is inconsistent and may be causing some of the problems.
Mid July- Reprogram AEM computer speed signal for the 7mgte engine instead of generic speed sensor. Seems to improve speed readings at the suprastick computer at lower speeds.
Late in July – Meet with Russels to troubleshoot with Suprastick computer. Reprogrammed the computer shift tables to factory settings. Tory determines that the torque converter is locking up in 3rd gear. Tory programs computer to not allow converter to lock until 4th gear is engaged.
Current – torque converter is still locking up in 3rd gear under more than 40% throttle. Under some conditions, car will sometimes shift normally between 2nd and 3rd gear (auto mode), but other times may hit rev limiter (especially while in manual mode and the car is shifted later than 5500 rpms).
Thanks for any help in advance!