Mopar transmission abruptly downshifts into second gear and will not shift until restarting engine?

Car is a 1993 Dodge Dynasty. I have noticed the speedometer goes haywire when the tranny acts up. I have replaced one of the speed sensors, I don't recall if it was the input or the output. I purchased both, but I could only locate one of the sensors. There is another sensor easily accessible, but I'm not sure what it is. I've been told the tranny goes into some kind of safe mode, and that some models required programming when the battery has been disconnected.This does not seem to be the case with the '93 model. It is the 4 speed O.D. with a computer mounted to the case. Any suggestions?|||the tranny i believe you have is the 41TE the first fully electronic transaxel chrysler made. the other guy is right it is in limp in mode... here's basically whats going on. an automatic transmission is either run by valves or electronically controlled by solenoids. on the 41TE you may notice you have Park, Reverse, Neutral, Drive, And Manual 1 but no manual 2... this is because there are only 2 solenoids on the tranny that in case of catistrophic failure can operate without the computer. one is second gear and the other is reverse... I just finished rebuilding those damn things for class as a final project and limp in mode could be caused by a number of things including if you heard a knock for a while and you noticed your performance decreasing thats a speed sensor or if you pull a speed related code it'll drop it into safety. it could either be the solenoid pack... which can be checked or a fouled up clutch pack thats inhibiting performance and forcing a safety...|||on the passenger side fire wall you will see a processor mounted with 4 bolts holding it on with 1 electrical plug in.....try this first...... used its only about $50.00.....if this doesn't fix it ....your forward clutches are getting burnt...its called limp mode and the transmission does not have to be programed ...besides there is no way to program your transmission...it is electronic and it is controlled by the processor on the firewall.....like i said if the processor doesnt fix it .....your forward clutches are gone