I just got to transmission rebuild 2 weeks ago I've never had this problem before until I got the transmission rebuilt. Sometimes the truck will crank and sometimes it will not so I could not trust it to carry it anywhere. They times that it will not crank I can turn the key over and everything is silent all the lights come on the dash the battery is a brand new the key is a communicating with anti-theft everything's good on that part. I could come back an hour later for the truck would crank. But in the last 5 days truck will not crank will not make no noise at all. I'll check the battery connection I have took the positive and the negative off and cleaned it all everything's good I'm also testing the solenoid with a screwdriver I'll hit did not start the truck so it's still good what is there left to do ?

 

If you didn't mention it we might not suspect it, but the problem it would seem is related to the MLPS (manual lever position switch which is located on the side of the transmission. If it was reinstalled without confirming the correct position it could be responsible for interrupting the circuit to the starter solenoid. Have you tried to start it in neutral? All this is assuming it is an automatic trans. All you need to do is have the people that did the trans work readjust that switch on the trans.
Let us know how you make out with this, thanks.