Have a 1969 Johnson 6 hp. Trying to replace the water pump. Got as far as removing the 4 nuts for the lower unit. Dropped down and trying to remove the nut for the shift rod. That thing is so tight I can't get it loose. Tried a screww driver (can't get on it with a 3/8 socket or nut driver. Even tried tapping it with a hammer and chisel. Won't budge. Soaked it with WD-40 and still nothing. Any other ideas. Here a very simple job turns into a nightmare. It won't move.No room to get on it with a wrench either. Don't want to heat it cause or ruining seals or anything else. HELP PLEASE.