1. Engine is cold or not tuned properly
    If the engine is not properly tuned or has not reached full operating temperature, the engine may not produce the necessary RPM to engage forward drive, or shift into high (second) gear. Learn how to tune your engine here.
  2. Transmission slipper clutch is slipping
    If the slipper clutch is set too loose, it will slip and not allow the vehicle to move. Tighten the slipper clutch.
  3. Binding shift fork-shaft
    Stop the truck and try shifting from forward to reverse and vise versa. Verify that the servo is pushing the linkage all the way into the transmission for forward gear.
  4. Throttle trim adjustment changed without reprogramming the OptiDrive® controller.
    The OptiDrive controller and the throttle trim is set at the factory and should not require adjustment. If you have adjusted the trim or replaced a servo then follow the instructions in this PDF for programming your OptiDrive unit.
  5. Drivetrain damage
    Inspect the drivehsafts and differentials for damage or missing screw pins
  6. Damaged transmission internals
    Remove, disassemble, and inpspect the internal gears for damage. Use your owners manual's exploded views for additional assistance.