Re: Trans over Temp
Welcome to the garage.
Which engine/transmission does your jeep have? Most probably the 4.7L or 5.7L engine? Both come with the 5-45RFE transmission.
I have red several stories about the transmission overtemp message. Most of the time it is a nuissance message caused by the TCM (transmission control module). Ofcourse you need to confirm if there is no real overheat, but many times the message pops up even on a cold transmission from what i heard of. The problem is that the TCM will change its shift schedule when it sees an overheat, which most probably is what you experience now as hard shifting.
Maybe someone who had this problem before can confirm, but as far as i know a new TCM should solve the problem (on the 4.7L and 5.7L, the TCM is part of the PCM, powertrain control module).
But what also needs to be checked is if no wiring is shaving against some metal part, causing a short.
Last possibility is the temperature sensor, but it is quite rare for them to fail.