One problem related to speed sensor has been reported for the 1996 Ford Windstar. The most recently reported issues are listed below.
When I get to about 35 mph, you can hear the speedo head gears grind. When you reach approx 55 - 60 mph, the speedo needle will bounce up to 90 and back, and keep doing this. We had the speed sensor replaced, but this did not fix the probelm. I was told by lompoc valley Ford in lompoc, CA that it is more than likely the speedo head. They also told me that they replace one of these a month, sometimes two a month. It seems to me that Ford should fix this problem instead of me paying the $1,000 that lompoc vally Ford quoted me to fix a problem that is obviously a manufacturer defect. Although this is not a big safety problem, it could turn into one because you either have to drive too slow for traffic conditions, or you don't know how fast you are really going when you try to keep up with traffic. I appreciate any help you can give me in getting this problem fixed.