This is what I have: 1996 Motor Guide ZX55 12/24 foot control bow mount. Now sometime around 2000 I replaced the lower unit with a 67# Hyperdrive 5 speed been bullet proof ever since. She is finally wore out I believe I am only getting less than 1 or full on. She also melted a red to the origonal switches gotta be replaced no doubt. My question is this can I install a 24 volt 75# 5 speed new lower unit on it? Shaft outside diameter is 1" measured with caliper on outside of lower shaft.