If your 85 is more like an 1983 odometer, rather than the 86+ odometer shown downthread, then you might have the same problem I had: it stopped on a xxxx9, either on the trip or on the regular odometer. The more 9's at the end, the harder it was to get it going. What was happening was that the lowest gear on the long spindle was slipping on the spindle, and would slip especially if it had extra resistance when it hits 9 (and has to turn two, three, or more dials at once). My fix was just to pull it all apart, whack the metal gear with a nail and hammer right near the center hole a few times, thus shrinking the hole just a bit, then jamming it back on the spindle.