Just finished my install, wondering if I have to fool any electronics (auto truck) in order to fire it up and check for leaks with no transmission in place.

 

dont think so...
you will have to by-pass the safety neutral switch or the starter wont enguage, also it might trip codes because the tranny is not hooked up, but that wont stop it from running (just clear codes later)
or for the starter leave ignition on and jumper the soilnoid (small wire) to have starter turn, be aware your engine might be tipped back enough for the fan to hit the shroud (something might break if this happens)