You need to install a new encoder first. The scenario you describe is exactly what they will do for a slipping belt/pulley ie: drive a certain distance and then code 32...since you have replaced the belt and pulleys the next step (and cheapest) is replace the encoder. Also I have seen where oil leaking out of the lift/lower valve spool will run down the encoder cable and fill the encoder up. There is no learn procedure for the encoder...just install and go. Check the connection of the encoder cable to the VM (Vehicle Manager) also. If encoder connection or new encoder does not fix the truck, you may have a bad VM. The VM generates a 5V supply to power the encoder...this 5V supply can be verified. Take off right side cover of VM and gently slide out the front panel (distribution board and VFC)...slide out about 5 inches...this expose a square circuit board on the left side of the VM box (power supply card)...look carefully and you will see several test loops...one labeled 5V. With truck powered up test for 5V at this loop...if nothing there...bad power supply card. Hope this helps.