I'm having trouble with the lower unit on a 74 Merc 1500 inline six. I just put a new control box and cables on the boat and the lower unit wont shift. I dont think it's related because even if I remove the cable and move the shift lever manually it wont shift. The shift shaft is turning in the leg as it should so I pulled the lower unit and spun the prop while holding the driveshaft. The shift shaft seems to be turning with the prop and jumps up in the lower unit when the prop spins. By the way the unit seems to be stuck in reverse. The control unit was replaced because the gear inside it broke in half. Do you suppose when the control box gear broke it was because of a lot of force being needed due to possibly a broken shift arm or a part that is frozen inside the lower unit? I drained the lower unit before removal and the oil was clean with no sign of metal in it. thanks for any help you can give, Devon
