Fontaine Fifth Wheel Ultra Coupling and Uncoupling Procedures…Never install the electric and air hoses until AFTER you’ve done the tug test. Connecting them should be the last thing you do prior to getting in the truck after you’ve done everything else.Why is it called the Fifth wheel? I assume it has nothing to do with the name “18 Wheeler” since that refers to the amount of tires on the cab and trailer combined.Also, truck cabs are referred to as tractors?And the legs for trailers are called landing gear? That one seems kinda odd to me since landing gear until now has only been the name that applies to planes, space shuttles, and helicopters. Legs seems like it’d have been a more fitting term since those things kinda seem like, well, legs for the trailer to stand on..