My Dad drove 18 Wheelers and that was what I learned to drive on. A 1968 Kenworth, 318 Detroit with a 4x4 transmission. Now 4x4 does not mean 4 wheel drive, it means dual 4 speed transmissions (2 sticks!)...16 forward gears and 4 reverse gears. He also made me learn to back a trailer before learning to drive forward. Dad was a SOB, but it cracks me up to watch people try to back trailers while looking thru the rear window and not using their outside mirrors.
Quick tip on backing, put your hand on the bottom of the steering wheel and move your hand the way you want the trailer to go.