Can anyone tell me the difference between the Oliver 22 and the 22A? Also when was the 22 built? I have what I was told is a 22A mower that I am rebuilding. I have the operator’s manual for the 22A and parts manual for the 22, 22A and 22B. The obvious difference between the A and B models is the main frame and the caster wheel frame. The first mower I bought has a cast iron gearbox top housing cover and the crankshaft cap is also cast iron. The parts manual shows stamped steel or plate steel for these parts. I just bought another mower that I am sure is a 22A model (it matches the pictures in the parts manual) with a manual lift.