A few weeks ago the speedo in my 96 explorer started to behave erraticly. The needle was bouncing up and down at all speeds. Also it apeared to show the speed about 10-20 km/h too slow. At this time the tranny was shifting very bad. After a about 5 days driving with this erratic speedo it stoped moveing at all. At this time I suspected that there was some problem with the VSS and I removed it for inspection. The plastic gear that drives the VSS apeared to be worn, not mutch but I replaced it with a new one. Now the speedo moves again but it still bounces erraticly and it still apeares to show the speed to slow. I talked with a tech at the local Ford shop and he said that had never seen this problem but his guess was that the VSS is broken, so I purchased a new one and replaced it. It made now difference. Now I'm realy stuck with this problem and I need your help.
Best reagards
Patrik from Sweden