Ever since I bought my truck its ran like a champ Ive loved the 4.10 gears, ran a 14.7 at the track with it, I couldnt be more pleased with it. Usually I would be at 2K rpm's at 70 mph now im at 2K rpm at 40-50mph. I dont understand it. I havent done anything different to the truck. It shifts into all 4 gears. My gas mileage is terrible now and I have a huge loss in power and my speedometer doesnt work. Is it possible for the computer to loose its tune and its acting goofy because it doesnt realize it has the 4.10 gears. I DID take the battery out multiple times to put in my camaro and drive it, but that shouldnt be a big problem. I put a new speed sensor in this past weekend and that didnt do anything. I can't think of anything else to do.

Any help would be awesome, Thank You.

 

If your speedo doesn't work and this is happening, I'd say you've got a transmission problem. The only thing that I could think of that you're revving that high at that low of speed is if you've lost overdrive or something. I don't know the internals of a transmission well enough to be able to answer your question 100%, but I have blown 2 out. The one thing that I do know is that the speedo mechanism is housed in the transmission. So that's where I'd start looking.

Good Luck, Hope it's something simple.

 

2wd or 4wd?

You said that it has all 4 gears? Impossible if it is at that high of a rpm if you have all 4 gears!!!

Do you have any access to a scan tool to watch the input signals?