The shift motor linkage includes a spring which is tensioned when a shift is pre-selected, and allows the low/high shift to be made by simply releasing the power momentarily. If the springs are weak or broken the shift will not be made fully and the gears will grind as soon as power is applied. Open up the shift motor assembly and look for weak or broken springs.
I purchased the shift motor new... Maybe it is defective? My assumption was that all the components would be good. Possibly NOT a good assumption.
The shift from low to high is perfect. Almost silent (I am VERY happy with that).
When a slight amount of power is applied in high range it seems to work OK. But when a lot of power or else hard variation on the gas pedal, it will slip out of gear and only be remedied by shifting into low range.
