Hi guys and girls,

i have a 2003 chevy silverado 2500hd. When drive it it shift fine 1st to 2nd to 3rd to 4th but 4th to overdrive it shift slow when i have the gas pedal down and i drive with hand controls and i have 285 tires on it and 3" lift on it. But i have to let off the gas pedal to shift quicker. What is it please let me know?

thanks
bryon

 

When you have the pedal down all the way, you are still accelerating and it won't go into overdrive till you back off the pedal and go at a steady speed.

 

Well if you still have the gas pedal down it still will shift but it takes sweet time to shift and I went to a transmission place and there was no codes on the computer and he told me it was my tires but I don't know but I try to put my hypertech tuner back on but it said code 68 on the tuner and call hypertech but it throw a service engine light on and I took it back to the guy and he said the tuner can not communicate to truck computer. He said call hypertech and tell them what is the problem and if hypertech won't do anything go to the dealer to flash my truck computer

Thanks
Bryon

 

A code 68 is an interruption during the programming session. Make sure you dont have any electrical acc operating at all. Make sure nothing is plugged in the cig lighter, if you have an aftermarket radio or amp or trailer brake you have to pull the fuse for them.

 

Thanks I just not want to rune my truck