I have a 1986 500sel AMG that is shifting terrible. It will only shift if
RPM's are high, over 3000 and you let off accelerator.
Fluid is OK. I checked the modulator valve with a vacuum pump to make sure
it would hold a vacuum and it does. the vacuum gauge on pump (with engine
idling) showed the vacuum to be in range. The filter has been replaced also.
Bad modulator valve??? Any ideas??? It just started doing this suddenly. We
don't drive this car very much either.