My '91 300E has a high pitched whining noise which seems to come from the odometer cable. I just replaced it and still get the noise. The occurrence is sporadic. sometimes when I get up to 70-80 mph it starts and continues until below 500 rpm. Also, sometimes when I get up to 40 mph and back off of the accelerator it starts and again continues to 500 rpm. Recently when I crossed a railroad crossing the bumps made it start at about 30 mph. Ha anyone else experienced this? Scott Egglefield

If the cable didn't do it, and..it's coming from the area of the speedometer/odometer, then it's probably the speedo head itself. Does the needle jerk around or is it smooth in it's action? But, you said a transmission noise, so I am a little confused about the location..