I'm sure this has been addressed in the past but I didnt see it. I recently purchased an 84 300D Euro. I noticed right away that when I get up to highway speeds (70 mph) it seems to run at very high rpm. I checked that it is shifting through all the gears so it seems to be a rear end problem??? Is this something I can do by myself and what can I expect to pay for one? Any advice is much appreciated.