3 speed overdrives were available in cars and trucks through late 69/early 70. I just looked at some 1960 car manuals that I have and there is no mention even of a 3 speed. They do list a 4 speed, powerglide and turboglide though. Information on OD's is likely in a supplement as there were so many different models and optional equipment available. There are complete sections on OD's in earlier publications as more were in use and auto transmissions were not as popular.
Fred
