I Have A Black Bear Tune And Tranny Question

2k8Vmax · July 31, 2010

Transmission shifting HARD on the 1-2 and 2-3 shifts.

i have a 2008 GMC Sierra, VortecMax, 4l70. I've had my black bear tune for almost a year now and have loved it.. my tranny tune doesn't shift much firmer than stock when you're light on the throttle, but its a lot firmer when you're agressive with the gas pedal.

So yesterday i go out and get in my truck that had been sitting for at least 3-4 hours since i parked it. After about ten minutes of driving i'm stopped at a light, i accelerate slowely (normal) and BAM, it slams into second gear. It shifted WAY firmer than the 1-2 shift at wide open throttle with the tune. HHMMmmm i let off the throttle and after a second BAM again, the shift into third. It did this all the way home, when i got home i turned the truck off and waited a minute. Then i started it and went around the block, it seemed fine for the first series of shifting, then...... BAM and the check engine light came on.

So i swapped the computers out and put my stockers back in, so i can take it in to the dealer. Well now i can't get it to do it. I tried running it hard up hill, ran it normal, ran it easy, ran it hard again and NOTHING now... could it be in the computers for the engine or tranny..?? I would the its the transmission itself, but like i said, i tried like hell to get it to do it again to take it in and it just wont...??

I figured i'll run the stockers for a few days and see if it will do it again, before i put the tuned ones back in and see if they do it... so no, i haven't tried the tuned ones since...

jwieps · July 31, 2010

Just a suggestion - If it goes away with the stock computers back in the truck, its not your trans. You could send tuned ones back and have them adjusted.

Jennabear · July 31, 2010

I will post what I posted in the other thread. Remember the tune tables don't change over time....

Bummer you didn't get the code read. There are certain things that will cause MAX line pressure (Such as MAF issue) and that code would have indicated what the problem was. Check your MAF, and intake tube, those are common issues. If the code pops up again, be sure to get it read.