DTC Codes help?

I have a 1996 dodge ram giving me codes 12, 77, 55 with the key on/off on/off on now its strange i cannot find a code that matches this 77...
I only ran the codes to attempt to find out why i am having strange issues... i started my truck and was driving down the road and noticed i was not shifting out of 3rd ( i have the 4 speed with push button o/d disable) so i pushed my button i then noticed my torque converter locked in then pushed it again (to turn the light back off) and it disengaged so i hit the gas and let off and it went in. Up untill this time i have had no problems with my trans. So i kept driving it and it seemed to shift fine then quit shifting again so i punched it again and let of and it shifted but then i went and drove around a parking lot with it (spinning my tires on snow) not hard tho .... and now i have a very irratic idle and it cuts in and out while driving and kicks in and out of 4th was wondering is there somthing that controlls the way the engine runs and the shifing of the trans that may have went out? such as my TPS? thanks for any help