I've got a 1983 240DL with the four speed manual transmission with automatic overdirve. If the outside temp is warm and the car has been running awhile, 30 miles at highway speeds, it won't drop into overdirve easily. The light comes on and you can tell it's trying to but I generally have to speed up to 65 or so to get it to drop into gear. Once in gear if I'm driving about 55 it has a hard time staying in gear. At one point the car was loaded down and had been driven 1000 miles or so and just stopped dropping onto overdrive. Once it cooled down it was fine. Is this a solenoid problem or do I need to replace the overdrive part of the transmission? Thanks for any help.