Been told there's a composite gear that fails in my mechanical, (not vacuum ) wiper motor. Bought a motor on eBay but linkage is different. Is there an aftermarket replacement motor available? Or some way to get wipers working? Also, a guy has a studebaker truck of same vintage and says he may have an overdrive unit laying around. He says the od units are for the most part interchangeable. Anyone know what make od will work? Thanks!