It sounds like you do not have much experience with adjusting automatic transmissions. Also, I believe your transmission is a 3-speed automatic, if it is like my 1972 350SL.

If your transmission is hard shifting, check the vacuum line. If it is OK and not broken then then I believe the modulator may have failed. If so, it needs to be replaced and not adjusted. It is important to adjust the new modulator properly. If you have no experience doing this you should take the car to a good mechanic who has experience with Mercedes transmissions.

230/8