you have and MXS has CAT ever updated it? sounds to me your Auto Valve Timing is not sending you a code i had that problem it would see a hill...
All shifts are 1150-1300 RPM and i run avg. 60 mph. also i use CAT 30 weight oil Lucas now offers it. BAYOU if your getting heavy soot around your...
Check your DATA Harness firewall to cab Warning disconnect batteries before disconnecting the plug you do not want to power surge the ECM...
Acert's like low rpm shifts 1300 rpm anything after that is just waisting fuel.... i get 6.8 mpg 90 day avg. 18spd/3:36 on 24.5 tires and gross...