Transmission trouble

I have a 1999 Ford Ranger with an automatic transmission and over 120,000 miles. My transmission does not shift automaticly all of the time. It is so infrequent that I just shift it my self. Also when I have to slow down due to traffic it gears down but shifts hard. Could this be my TPS or the Ford equilivant? I also don’t have a speedometer.

I assume that the truck actually does have a speedometer, but that it does not work.
Is that correct?

If that is the case, the non-functioning speedometer and the inconsistent transmission performance both point toward a bad Vehicle Speed Sensor (VSS). Replacing the VSS should–hopefully–restore both to working order.

Please note that this answer presumes that you have changed the transmission fluid and filter every 30k miles. If you have not, then replacing the VSS may only fix your speedometer problem.