also check you throttle position sensor my 95 was doing similar things.
if you want to see the trans errors
1: turn on main power (do not start )
2: push the up an down arrow on the shift pad (you should see the display change to d1 fallowed buy numbers )
3: push and hold the mode button you will hear a beep keep holding till the second beep (this clears all your error codes )
4: start the truck and re create the problem you have then shut down
5: turn on main power (do not start )
6: push the up an down arrow on the shift pad (you should see the display change to d1 fallowed buy numbers write them down)
7: push the mode for the next error code , keep cycling through and writing them down untill you see the first code or some strange characters
8: look at page 38 to 50 in this
http://truckroadservice.com/barth_attachments/virus.pdf
my errors are 44 13 and 33 23
44 13 is Short-to-ground, B solenoid circuit
33 23 is Sump oil temperature sensor,failed high
and i replaced the throttle sensor and fixed my
21 23 Throttle position sensor, failed high