The computer needs to be programmed. The last time I tried to have a dealer do this they wanted a day plus normal shop rates. Doing some math and visiting a local shop should be quicker and cheaper.
What do I need to have the dealer change so the odometer and speedometer are accurate. I went from 3.73 to 4.10 gears and now have a 10% speed and distance error.
I've got a Hypertech Power Programmer III for my '04 Avalanche. It allows me to modify the PCM programming for different axle ratios (your ratios are one of them), shift points, rev and speed limiter, and various regular and premium fuel power profiles. It also does OBDII code reading and clearing. The model I have is specific to '04-05 GM/Chev/Cadillac/Hummer trucks with
4.3, 4.8, 5.3, 6.0 and 8.1 engines. Part number 30022. I couldn't live without it. A couple of hundred or so.
Thanks for the info. If my local dealers don't know how to change the computer, I will look into the programmer you mentioned above.
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