1971 Mercedes Benz 220D

I have owned this vehicle since 1976. I was driving it up until about 10 years ago when I started replacing the heater fan motor. I had no manual and began removing dashboard components. This turned out to be much more of a job than I imagined so I gave up and the vehicle has sat in my driveway since. There are some rusted out areas and paint is badly faded. Headliner sags at back. Automatic transmission tends to not shift out of first gear unless you let up on accelerator pedal. Shifting is controlled by speed and throttle position so adjusting the throttle rod may fix this.