Garage Cabinets, Garage Storage, and Garage Organization

96 S320 firm upshifts
I am writing about hard upshifts on my 96 S 320. I just bought the car with 65K original miles. The firm upshifts occur in all gears, and I have noticed a minor leak in the white plastic "L" shaped plug adapter that is mounted on the passenger side of the transmission. I also noticed that the problem is more severe at higher altitude than at sea level. Prior to my private party purchase the dealer indicated that, in my case, firm upshifts are an external transmission problem not internal, which was good news, and recommends a new plug adapter, cable links, and adjustment. The car has not yet had the 60,000 mile service, which would include the transmission service. My limited experience with the dealer indicates that their advice may be good but charges are a bit suspicious. They quoted $250 to unplug and remove and reinstall my trunk mounted cd changer which took me 10 minutes doing it myself. (unplug the unit and removing 2 mounting screws)

I was quoted $550 for the above transmission work and $1250 for a standard 60K service. Any useful comments and experiences related both to the problem and the cure, and the associated repair quotes, would be very appreciated.