Go back and check out the electrical system again before you remove the trans. Any of the following components will give you the condition you described: Relay, govenor, solenoid, and blown fuse.
Fred


1956 3100 Pickup/Red/350/3sp OD/PS/Disc Brakes
1957 Bel Air Sport Coupe/Red/355/TH350/PS/Disc Brakes
2017 Silverado LT Single Cab SB/Black/5.3/6 Speed Trans
1947 Willys CJ2A w/F-Head engine