Purdy Swoft
Well-known member
As for STP oil treatment , The last bottle that I got , the label stated that it is a lubricant . The model A transmission and backends are very forgiving . Just about any heavy gear lubricant will work in the model A transmission . I have used the mixed version gear oil sold by model A parts vendors with good results . I also have used straight STP , Lucas oil stabilizer or straight 90 weight gear oil with good results and no problems .