Before you spend much time figuring out the slider issue, you should check your door pillar sticker and compare it to the specs of the 5th wheel. The trailer towing capacity and payload of a "1/2 ton" truck can vary by so much that the term means almost nothing anymore. You need to know how much trailer you can haul and how much payload you have available for the pin.
As an example, a current Silverado 1500 SBCC can be rated as much as 10,500lb trailer weight for a 5th wheel, but it can be rated as low as 6300lb. Your door pillar sticker will tell the story.
