My 1983 240D is shifting really late. Going from 3rd to 4th gear is only achieved when I hit 60 MPH. All of the other gears are shifting late as well. I was adjusting the 'key' in the modulator on the transmission, but was told that it only controls for controls how smooth it shifts, not when. Any help would be great. I am ruining my engine by the higher RPM's. Fluid is good; red. Problem started when I had both the valves adjusted and the key lock assembly replaced.
1983 240D 220K
1988 260E 198K