Crash 86

first off im new here so id like to say hello to everyone, i just picked up my toyota but it has some transmission issues. i start it up and immediately my at trans fluid warning light comes on, the truck will not engauge in reverse, but goes into drive and all other subsequent forward gears extremely hard like the stall in the converter is engage, the truck is idling fine by the way. after about fifteen minutes of running the tranny no longer goes into drive. i pulled the dipstick from the transmission and its barely luke warm, the fluid isnt dirty or burnt smelling. was wondering if it was one of the solenoids or could my temp sensor be causing all of this. dont wanna play the guessing game here.