Hi All I have a 2003 4.8 and are currently running 285/75/16 muddies. My speedometer is about 15% slower and the odometer is 10% over. Any suggestions on how to rectify this. My initial thought is that the previous owner had bigger rubber on and changed the diff ratio :rolleyes:. Any thoughts...

Hey all, I'm considering changing my 4.1 ratio to 4.3 or 4.6 for lower 4L and to raise the engine RPM for the hiway. Its a 93 GQ td42 with the 4 spd automatic with TC lockup. Currently 4L just isnt low enough, and on the hiway with the torque converter locked up it runs around 1800 rpm at 110kph...