Good morning,

I have a 2008 Cobalt with a TCC that like to lock/unlock on flat ground and a constant speed. (I have a log of this). I tweaked some of the TCC max and min DC values and the problem went away for about 650 miles (one trip). I did some basic tests on my TCC and it seems to behaving correctly. I have read that the T42 has had logic issues with the Transmission Adaptive Pressure Shifting logic. I want to see if my problem is actually TAPS or something else. The reason I believe it went away at first is because that was the first tune I have ever put on my module thus resetting the TAPS logic. Now that I have ran some time with it the logic is recorrupting like a corrupt memory address. If I do a write entire will that reset my TAPS values again? or will it harm anything? My thoughts are if I can confirm that it is corrupt logic, Ill just buy a different TCM which brings me to my next question. Can I buy a T42 from the bone yard with matching service numbers and re-vin it for my vehicle? Then write entire to have the proper calibration on it? Or is it just easier to order one programmed for my vehicle specifically?

If anybody could give me some insight it would be greatly appreciated!

 

I had adaptive pressure turned off completely and this problem remained until I maxed the TCC values to 100/90. A part throttle surge during cruise between 14-1600rpm in all gears.

 

How did you disable your adaptive pressure? I did try to 100/90 but it just seemed so aggressive. Do you still run lockout in 3rd then? How many miles have you put on your transmission running this setup if you don't mind me asking?

 

How to disable adaptive at the bottom of the page. I run 100/90 in 4th only. 3rd is way too damn jumpy. I have the enable speed set to a lower speed in 4th gear than the 3-4 shift. Lockup is completely disabled in 3rd gear now. I've been this way for... what? Like 40,000 miles?

 

I modded the cal similar to yours and havn't had any TCC issues, but again, I will have to wait some time to see if it reappears.

Thanks!

 

 

10k miles later, no issues. Thanks Bud!

 

Wow jesse actually being helpful. Look at that.