By now you probably have removed the wheel, or had someone else do it. I have 2 MTD 38" lawn tractors of the same vintage and type. I had to remove the transaxel on one of them in order to use a support rig and sledge hammer. Success took hours of pounding and penetrating oil. I now use anti-sieze grease on the wheel.
I'm have not been able to remove the second set of wheels yet. I may need to bring it to a dealer as wheel pullers and sledge hammers have not worked.