smoked a 3-4 clutchh in the old trans then bought a truck with a bad frame that drove fine trans shifted through all gear. i rebuilt my motor at the same time as it had 240k miles all is back in and still no shift past second. 1-2 manual is fine then is will not go back to first unless is do it manually. if i go into 3rd manual it is like neutral almost like a bad clutch pack but the trans worked in the other truck. i have power to the trans

 

You will need to connect some type of scanner to the OBD port to see if the PCM or TCM is commanding the shift. While you’re there check for any codes.

 

First Unplug the harness and drive you should be able to manual shift 2-3 you will not be able to shift to 1st or 4th but this will tell you about the integrity of the 3-4 clutch set if it works like this then it should work with the vehicle if proper command is given , If it still feel s like neutral you have a bad trans.
Note this will set codes you have to clear afterward.

 

i have a code for loss of communication with pcm the 3-4 clutch pack is fine my scanner can't read for shift commands