I have a 09 Silverado 1500 LT, 5.3 flex, 3:42 gears, 22in tires, I want to change the gear to a 3:73, the dealership says GM doesn't have a program for tires and gear changes. I was told Hypertech has a programmer just for gear and tire changes to correct the speedometer, does anyone know if it works?, or does anyone have any suggestions, Thanks, Ken.

 

Either I'm misinterpreting this or you are.(50-50 chance either way) When you do a gear change, you have to reprogram your PCM to tell it that you've changed gears at your differentials, but the programmer isn't going to make a gear change for you. You change the gears, at which point your truck's PCM still thinks it has the original gearing. This results in an incorrect speed registering on your speedometer, and your ABS and Brake Warnings on your dash all lighting up. Then, any handheld programmer(Mine's a Diablo, for instance.) will reset the gear ratio and wheel INFORMATION in the PCM, and clear up your speedometer accuracy, and your ABS alarms.

FIRST, however, you have to remove the 342 gears, purchase the 373 gears, and install them in the differentials.(@2000$ at a decent shop)

Bear in mind that while the 373 is a better all-around gear, especially if you need low end power a lot, you'll lose highway gas economy if you do a lot of traveling.

When you're having the gears changed, you may want to see if they'll reprogram the PCM for you at the same time.

**A word of caution, if you do this without written permission from your dealer, you can kiss your warranty goodbye. So you may want to think about holding off till your tires wear out, your warranty expires, then do rims,gears, tires and alignment all at once.