I noticed that the transmission fluid on my '93 300E 2.8 is losing its bright red color and gradually turning pink (and soon will become brown). I drained and refilled the transmission and torque converter about 300 miles ago (the fluid level is correct, I checked it several times) and have been doing mostly city driving since. The fluid I used was Valvoline Dextron III. Are these transmissions supposed to run hot, or is something else burning the fluid? Perhaps I should change it again and use the MB synthetic fluid or maybe Mobil 1 synthetic tanny fluid. I've only had this car for a few months, so I'm not yet familiar with this particular MB transmission design.