My grandson bought a 94 f150 truck. The steering gear box popped the bolts off the frame. I purchased a rebuilt box, bolted it up, installed pitman arm,,,,but I am unable to start splined shaft back on new box,,,,,,I tried putting old box back on to check and see if splines were different, but I can not get it to start on shaft either,,,,,I must be missing something.....HELP.