Skirk55:
This subject has been discussed at length on the Forum, and many opinions, suggestions have been given. Gary's comments sum them up quite well.
I have the same problem, or so it seems. There is also a difference of opinion of just what the term "chucking" means. Is it an 'up-down' motion or like mine, a front-to-back motion?
I am not convinced that the "hitch is not the problem", as some of the adjustments I have made have lessened the sensation that I am getting.
I have had the trailer pulled by a friend's truck which is similar to mine and during that test ride, we did not experience any sensation (chucking, forward-backward), therefore I cannot eliminate the truck setup or the hitch setup at this point. The main difference was the hitch was different as his was a single pivot hitch of different manufacture. I have made adjustments to my hitch itself: lowered it to absolutely level at 5 inches above the truck box. I have adjusted the tension screw in the front of the hitch which absorbs the play between the front of the clamps and the locking bar. (Hitch is a HIJACKER 18K double pivot).Weights are within "forum suggested norms" for the weight of my trailer. Weight on the hitch pin is 20 to 25%.
I cannot do any more testing until spring, ie: May next year since the trailer and truck are now in storage for the winter.
At this time, I'm not prepared to spend $1000. or more on an air-ride hitch or pinbox attachment, even tho' it may eventually be the way to go.
If you would like to use the private message route to discuss this with me, I'd be happy to do so. If we come up with some positive results, either of us could then post the summary of any testing and ideas that help to the forum, so that anyone who could benefit from it can see it.