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View Full Version : tranny/converter problem..need help



sdb
September 20th, 2006, 02:14 PM
2000 SS auto

OK....installed a 3600 stall converter, built tranny, lots of mods. Car bogs at the track and street from a dead stop, won' spin tires at all. At about 4500 rpm, car feels normal, and at a high mph kick, it feels fine. Tranny shifts perfect, feels fine. Converter feels good except at WOT from a dead stop. Seems like the converter is locked while in first gear at WOT...it just drags and drags until about 4500 then the car comes alive. I have some things to try per converter manufacturer.
1.) Try the car in 1st and reverse, see if it feels different than in D or OD (due to line pressure increase).

2.) monitor engine to make sure its not taking out timing (KR) at WOT from a dead stop.

3.) remove pan, unbolt TCC solenoid, and drive the car to see if it acts differently since it won't be able to lock up at this point.

Can the forum think of any other things I could try?

Don't wan't to name the converter company or transmission company since I have seen how people can get the wrong idea and "bash" vendors without knowing all the info!
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scanned with EFI Live....I noticed that the Torque Converter Apply Duty Cycle is about 98% at WOT as well as cruising. I dont know if this is the right thing to look at though!

It seems to be a little snappier when I manually shift it, and it will spin the tires if I brake stall it to about 2600 (in D)....as compared to just hitting it in D from a dead stop.

I am able to lock and unlock it with the EFI Live at will, seems to lock and unlock fine with using the brake pedal to unlock or the EFI live to turn the TCC solenoid on or off.

What do I look at to see if TCCis being commanded on EFI Live?
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Any thoughts?

SDB

SSpdDmon
September 20th, 2006, 11:55 PM
Hmmm....what kind of tires are you running? Rear end gear ratio?

joecar
September 21st, 2006, 03:23 AM
Log GM.TCCMODE to see if the PCM is locking the TCC.

Locking the TCC requires 2 soleoids to be commanded:
- TCC PWM (Apply) Solenoid
- TCC (Enable) Solenoid

So, in addition to GM.TCCDC, also log and GM.TSTATE00 and/or GM.TSTATE01.

Edit: the Tune Tool allows you to control the when the TCC locks/unlocks, but first answer SSpdDmon's 2 questions.

sdb
September 21st, 2006, 05:41 AM
OK...I have EFI Live Pro V6...am I able to log these things, and if so how? I usually just hook up my laptop and look at basic stuff like KR, shift rpm, etc.

Thanks for the input

SDB

jfpilla
September 21st, 2006, 08:48 AM
Based on your description of the problem, it's not likely that the converter is locked in 1st or your car would stall. However, set D2801 to "NO", just in case. That should keep it from locking after each shift.

Does starting in 1st feel any different than starting in 2nd?(is starting in 2nd only a C5 feature)?

What's been done about torque management?

It does sound like it's starting in a higher gear.

joecar
September 21st, 2006, 09:05 AM
I thought V6 Pro allowed you to see the GM "Enhanced" PID's...

joecar
September 21st, 2006, 12:10 PM
Ok, sounds like you first have to check if trans is starting/shifting correctly:

a. pull gear lever into 1, and accelerate from a stop (stays in 1st, observe RPM at 30 MPH);

b. pull gear lever into 2, and accerlerate from a stop (stays in 2nd, observe RPM at 30 MPH);

c. pull gear lever into 3, and accelerate from a stop (should start in 1st, shift to 2nd and then to 3rd, observe RPM in each gear if you can, should progressively drop with each shift);

d. at 30MPH in 3rd, increase throttle some amount, should downshift, does it...?
immediately after downshifting, reduce throttle some amount, should upshift, does it...?

From doing those 4 things, you should be able to see if your trans. is starting in the correct gear and if it's shifting;

Is the PCM not throwing any DTC's...?