I am mixing and matching lower units for a 70 hp evinrude 1974/75.. the lower shaft looks like an replaceable part or the top part does, depending on how you look at it.. The sierra catalogue shows it as 2 parts.. does anyone know how it comes apart? it looks like it might just unscrew but if anyone has experience in this, could you please pass it on....the lower part fits in the lower unit and comes up into the water pump where the upper driveshaft I beleave screws into it.. Can someone help me out? the manuals, just show it as one unit..<br />tks.<br />Stan.