Will a transmission from a 1955 Oldsmobile fit on a 1956 Oldsmobile 324?

 

A 1956 88 came with the Dual Range (Slant Pan) HydraMatic transmission (like the 1955 trans) and the '56 S-88 and 98 had the new JetAway HydraMatic. To answer your question, it depends on the crankshaft. The Dual Range transmission requires the crank to be drilled with a pilot bushig installed and the JetAway does not. Check the flywheel end of the crank and you will know. The flywneels are also different.