Around 1961 I was riding with a friend who had a stock 40 Ford sedan except for a stock 50 Olds engine. He had replaced the transmission a couple times before and had swore off mistreating it. He said words to the effect, "I need to go easy tonight, I don't want to break another trans". About that time another car pulled next to him at a traffic light. The light turn green, you know the rest. The next day I helped him replace another one.