Truck will not go into park, engine does not crank while in park

Originally had a lot of loose slack in the parking/drive/reverse shifter on the steering column. After taking it to the mechanic, he found the problem. Had to put new bolts in the face place that secures the steering/shifting rods firmly to the truck's firewall (the area right above the gas pedals). After securing the face plate with new bolts, now the truck will not go into park, I cannot crank the truck in park. I have to now crank it in neutral and "park" it in L,1, or 2. The mechanic said "it is a bushing or a sensor that is not engaging/clicking into place". He is currently too busy to fix it, and is going out of town soon after. Please help, I am not familiar with this territory. Thanks, D