You will have to pull the trans pan and see if the wires from the 4 wire harness are connected ie, TCC, 3rd, 4th gear switches. These switches do go bad thou, very easy to find at the junk yard. Have you had you trans built? I had a bad experience with a guy who had stolen my valve body and servo and replaced it with some BS, my problem was the valve body I had only had a fourth gear PS.... Good luck..
Their is a few way in identifying a VB. Their are two pressure switches in the BRF valve bodie, they are unmistakable, with wires running to each switch. The second way to identify, the VB should have BR3 in black writing on the side of the VB. Go to Gnttype.org, to the technical picture section and the have pictures of the right pieces that you need for your trans.