A customer brings in a vehicle that won’t move forward, backward or both.
Check first to see if it grinds or clicks. And does the speedometer read a lot higher than you’re actually going?
Chances are the driveshaft is disengaged. This can happen if the vehicle had earlier transmission or body shop work and the driveshafts weren’t properly reinstalled. If the vehicle has VTM-4, power transmitted through the VTM-4 differential will let it move slowly for short distances.
To fix this problem, check for damaged splines on the driveshaft and on the intermediate shaft, if applicable. If the splines are OK, replace the set ring, reengage the driveshaft and test-drive the vehicle. If the splines are damaged, make whatever repairs are needed.