Mercedes: 81 300D, revolutions per minute, vacuum pump

Question
any important advice for buying an 81 ?  shifts hard, seems to have high RPMs between gears. Found to be common with Mercedes  sellers says some frame work needed. seems worst in front of rear tires.  Plus what is the best source for maintenance and parts? thnx

Answer
Toni,
You did not indicate the mileage,  but the high shift revolutions per minute, may indicate slippage of the bands. If so this could be a very expensive repair. Because diesels do not  have a source of vacuum from the engine, but rather use a vacuum pump you should expect some expense  if this unit is fails.
If this vehicle has frame rust, I would steer clear, as this may be an indication of much worse frame and body damage.
Hope this helps
Professorbob