I've got 4.88 gears and 395/70/16 tires. My speedometer is currently 10mph too fast. I know there's calculators online but I just bought this truck and have no idea what the drive teeth number on the transmission side is. Any links to what I need would be greatly appreciated. Its a 97 silverado 1500 automatic 4wd. Thanks guys!

 

Buy a programmer that'll let you correct it or get a custom tune done to correct it

 

Was hoping to do a mechanical fix by installing the correct number of teeth on the spedo gear. At least, that's how I did my jeeps. Plus, it'll save me hundreds of $ by just buying the correct spedo gear

 

As stated above a programmer is your best bet.

Your 4L60E trans has a electronic speed sensor that sends the signal to the ECM to read correctly for the specific vehicle's tire and gear ratio.

I'm not even sure different speedo gears for the trans tail housing are even available.

 

^ don't think so either. I believe you can either live with it or find a programmer on Craigslist/eBay for cheap. Make sure whoever had of before you though, has erased it off their vehicle

 

Well that's upsetting. I would much rather buy a $30 spedo gear with the appropriate teeth than a $250 programmer. Grrrrr. Cheapest one on eBay is a hypertech for $200. No thanks ha. Thanks for the help guys.

 

Lots of 2wd transmissions or transfer cases have an electronic spedo. The spedo gear simply connects into the electronic housing and pops into the tranny/transfer case typically with a c-clip and one 10mm bolt. That's always how I've settled the speedometer reading issue on my off road rigs. I'm very surprised Chevy doesn't utilize it.

 

There are $200 programmers that provide readouts of the error codes and allow you to change the settings for the speedometer on most trucks. Be sure to check that it covers your truck and decide whether it is worth the $200.