I have a 96 grand cherokee 5.2L AWD. Recently rebuilt trans and now its not shifting into overdrive. It has a P0783 code (3-4 shift malfunction). I dropped valvebody and replaced overdrive shift solenoid pack. Didn't change a thing. Does anyone have a flow chart for this code or recommend anything? Trans fluid temp reads fine on scanner. My mt2500 snap-on scanner will not give any trans related tips.  

Sorry in my job I am only familiar with the 4l80E for electronic transmissions. The 4l80e has a 1-2 shift solenoid also a 3-4 shift solenoid. I believe this transmission does as well. It could be as simple as your solenoid is dead. If your not getting any other dtc's I would be looking to replace this before tearing your tranny back apart. Look very carefully for the simple. Ie connections on the ends and so on. I found this info on the web it may help. It covers your family of transmissions. I didnt see where it stated your code specifically.

http://colorado4wheel.com/allmanuals/Jeep/KJ/03_KJ_FSM_Includes_Diesel/15887-kjtr_sgmldiag.pdf