ok, now that the custom tune is settle. and everything started fine, but when i put my truck on reverse. nothing happens. put it on drive . still nothing happens. what could this be?

 

BTW, the truck has automatic tranny

 

if all you did was change the tune.Put the stock tune back on and call your tuner

 

ok i'll try that .

 

well, it's not the tune, i've set it back to original, the same. and i got a new tune from a new vendor still not engaging. i'll put it on drive and it'll take about 3 to 4 seconds before it'll catch the gear and when it does , it does not seem like it's grabing on 100 percent. and disconnects after 3-5 seconds. what is wrong?

 

Try posting in the tranny forum,
My guess is that if this issue showed up right after putting in a tune,the pressure selonoid in the tranny may need replacing...but dont take that to the bank.Get it checked out