600W Oil was used in Model A transmissions, differentials and steering boxes when they were first manufactured. It was the oil weight of Henrys choice and it must have done its job as so many Model As have survived till today. With change in the industry, and with little in the way of a technical specification for the 600W oil and that Henry changed specifications as he developed newer cars, the original 600W oil became harder to find resulting in many car owners using any oil they could find. With these newer oils, people did often notice the puddles underneath their cars but they thought was normal for a Model A. The saying went “If it wasn’t leaking it must be empty”.
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