Jays right. The transmission and transaxle are identical in both cars. The difference probably is in the drive axle layout. Do know the Caddy ran one axle through the oil pan but don't know if the Olds used the same layout.
The GM Motorhome used this transaxle as well but usually with the Olds engine. The 500 Caddy really made these things dance, well as much as a 8,000 lb anything can dance. If I could find one of these motorhomes in reasonable shape I would pick it up in a heart beat assuming the price was right. The only real attempt to make a purpose built vehicle from the ground up, as opposed to gluing a box on someone elses chassis.
Bill