Hi All,

On my 1984 300D, I recently swapped in a 1985 differential and with it a 1985 speedometer. I drove around for a few months and all was fine except the mileage was wrong, so I pulled it out and updated it to the current mileage.

Right now, the mileage is correct and is incrementing properly, however the speedo reads about half what it should.

I had the same problem a year ago after puling the instrument panel and I thought it was my speedo cable, so I replaced it. Unfortunately, that has done nothing to show the correct speed.

My understanding after doing some research is that if the odometer increments properly, the problem is inside the speedometer. My only thought is perhaps it needs some lubrication. When I run it off a drill and square bit, the needle doesn't move. Also, sometimes it will not go back to zero when parked.

What else can I do or check here?

Thanks,

Dkr.