A fifth wheel hitch is a trailer hitch used primarily on full-size pickup trucks. Depending on the style of fifth wheel hitch used and the length of the truck bed, a pin box extension might be necessary.
A standard fifth wheel trailer hitch is designed primarily for use on a long bed truck (a truck with a bed longer than eight feet in length). For a short bed truck, either a slider hitch or an extended standard hitch is required.
The danger of using a standard fifth wheel hitch on a short bed truck is that there is not enough space between the trailer and the cab of the truck, resulting in the potential for them to strike when the truck turns.
A pin box extension is used to make a standard fifth wheel hitch suitable for use on a short bed truck. It creates the necessary space between the trailer and the cab and prevents them from colliding during turns.
