Ford Repair: e4od transmission, rear differential, ford f150

Question
i have a 93 ford f150 which i drove home from work one night and the tranny shifted fine the next morning when i went to go to work the tranny shifted really hard and would not go into high gear also the speedo was jumping all over the place,a couple of days later the tranny started shifting okay.i pulled the pan off and changed the oil and filter and there was no sign of metal filings or excessive wear on the clutches in the pan. any suggestions on the problem?

Answer
The problem is with the speed sensor (or its wiring) which is attached to the top of the rear differential.  About 95% of the time the sensor itself is bad, so I would replace that first.  Get a Ford one, if you can even find an aftermarket one, it will not last long.  The sensor will be rusted in so spray it with lots of penetrating oil and carefully twist and pull it out with a pliers.  It is plastic so be careful not to break it off.  If you keep driving it that way, the transmission will fail because it needs to know vehicle speed or it can't shift correctly.  Your speedometer also reads vehicle speed from that sensor, that's why it was erratic.  Hope this helps,
Jason