93 300d 2.5 turbo wont up shift to 4th when outside temp drops. changed oil @ filter. seems to shift more smoothly. this is my first mb. love it ! now a former bmw owner. any info would be helpful. only 76800 mi on the car. cannot seem to find a trouble shooting manual . i thought i saw the same problem listed but there was no responce. help please! thank you yankee