Hi everyone, I need info on how to get the right speed readout from my speedometer. I have a F-150 2006 4.2 engine with 5 speed manual transmission with a 17" factory wheels and a 355 rear axle and changed the rear axle with a 308 8.8. my speed is reading about 5 miles below what used to be.

What do I need to get the right speed reading?

thanks in advance
Jorge Gonzalez.

 

Some programmers let you adjust the speedometer, but I have never used one to tell you the details exactly.

 

Check with your local dealer to see what gear that goes with the 3.08 gears. It should beas simple as removing the VSS and replacing the plastic gear.

 

you can probably just hook it up to a good scan tool, and change it. Theres quite alot that you can do with them now-a-days. It wouldnt be to bad if you took it to a dealer and had them do it for you either.