To check if trailer frame is parallel to ground. Find a flat level spot for truck/trailer. Measure main rails (not fifth wheel platform portion of frame) of frame aa far forward as possible to ground . Then measure main frame rails to ground, as far back as possible. If frame is in the proper position -both front and rear measurements will be nearly the same. Much more than an 1" higher front measurement compromises suspension travel of rear axle. Lack of suspension travel amplifies the normal push-pull of a fifth wheel hitch system.
