Hi all,
I recently purchaced an '87 300D with 220,000 on the clock. The A/C was not working when I bought the car. I added two cans of R-12 and the die to begin to find the leak.

The air blows cold now, however, with the A/C on, the transmission shifts much harder and downshifts to 3rd gear with only a very slight increase in throttle pressure over 60 mph. It is then very reluctant to shift back to 4th and almost requires a quick move of the shifter to neutral and then back to drive.

Oddly, I pushed to full throttle on one occasion with it "stuck" in third and it downshifted to second at about 65mph. Tach went to 5100rpm! VERY SCARRY !!! I had to let completely off the throttle to get to third and then coax it into 4th. Next slight grade, roll in 1/2" of additional throttle and back to third.

I have studied the previous threads and have a rudementary understanding of the Bowden Cable and the vaccuum modulator but did not find this specific problem.

Two questions...

1) Why would the car run so well without A/C and have this problem with it functioning and on.

2) Is this more likely vaccuum related or Bowden Cable?

Any help is greatly appreciated. I am really looking forward to getting her road trip ready. This is my 4th Mercedes but my first Diesel.

BR,

Steve (8C>