Working on the forklift, the operator stated that when the gear swith is in the forward position the lift moves forward when the steering wheel is turned one way and reverse when the wheel is turned the other way, all while the shift lever is in the forward position. The truck moves very slowly in either direction. Same happens when the shift lever is in the reverse position. No error codes come up, even using diagnostics. Battery is fully charged; no fuse is blown; all other operations work fine. Any ideas on where to start looking for the problem?