my Speedo
 

Cover your eyes! :icon_banana: My speedometer works, but the odometer doesn't. any help? 1990 D250. and how can I tell if I have positraction? (it's 2WD) ... Thanks, Jim

If the speedo works and the odometer doesn't the whole assembly will have to be replaced.

Jack up the rear wheels and turn one by hand while watching the others direction of rotation. If they rotate in the same direction it is a posi. Other wise you can open the differential and look at it.

Is there a place that repairs them? I've got the same problem. I see a lot of guys with the same problem and figure the used ones will be junk also.

mine has 370,000km on it and it still works. had it installed in my 81 about a month ago. i would at least try the one from the junkyard. you could probably test it right there at the junk yard if you grab the plugs that go to it. run power to the positive and negative terminal on the speedo which should also make the voltage gauge start working and then keeping touch the the 3rd terminal on the speedo to the negative terminal as quick as possible as many times as possible and the speedo should move and trip-o-meter should also move.