I am running a 33" tires with 4.10 gears on an automatic tranny. I need to have my speedo calibrated. I am hearing a lot about other options such as Superchips, Skyjacker Truspeed, and orange (35 tooth) speedo gear.
Which one will work better? Anyone have used any of these?
I have 33" wheels and 4.10 gearing. I put in a 36 tooth speedo gear and its right on. You can get the speedo gear from Quadratec but its like $40!! I bought mine used off EBAY for 12.75 shipped and it took two seconds to change. I would recommend that, I'm not sure the speedometer is controlled in such a way that a tuner would fix it, at least I never heard of that as an option!
I just changed mine this week as well. It went really fast except that I put it in upside down the first time and it didn't register. I don't know if an Auto will make a difference but I wouldn't think so since the speedo gear is in the back of the transfer case.
Here is another link that will help in installing the gear.