You could try a set of "Velvet Ride" shackles. I've seen them advertised for many years on TV (spike tv I think). They are soft when the bed is unloaded. And when the bed is loaded they settle down to provide full capacity.

I've never used them nor have I known anyone that has used them. And I've never checked into how well they work. I just know they exist.

 

I agree with what's being said. An unloaded bed is a minimal load for a Dakota's springs, and the rear shocks are adequate at best. I've put *alot* of weight in the bed and always stayed clear of the stops.