Cabover struts?

Most of us are running E rated tires at 80psi when the camper is loaded. It makes a big difference in hadling and safety to have the proper tires and pressure

In your photos, it shows the stabilizing bar. It goes across bed horizontally. The bar isued do the thinness of the truck beds. Pictures indicate the FT-DR series brackets. Weight can still be issue.
Check the air prssure in the bags. See if camper is sitting on the springs and not supported by the air bags.

Ive noticed this movement in mine as well, I just had to keep telling myself its normal. I could actually look up through the windshield and see the nose of the cab over section moving lol. Its never going to be like you mentioned (as one solid unit though) Because the frame of a truck is made to twist a little bit, Its made to give just a little between bed and cab for going over rough twisty roads. So if your anchored just to the bed alone which is what I recommend your going to notice some of this movement for say as you go over a bumb or rough place in the road because the bed which your anchored to goes over the bumb after the steer tires. I remember when I was a kid and would ride in back of the truck that you could witness this by the gap between the top of bed and back of cab moving, changing/ and would actually pinch your fingers if you held on there. OUCH , Only happened one though. I would think the heavier duty trucks may have less of this movement but that's only a guess. I look at it now as 2 separate units, The cab/ and then the bed section that your mounted which is designed to move and twist a little at times independently from the cab. Just my 2 cents on the subject. And I would think you could actually damage a TC by strapping the nose section to snugly to the front of truck because your making it twist when the frame does. Or trying to make it do this= eventually something's going to give. I don't have any experience with any trucks between a 3/4 ton Dodge and the freightliner I recently purchased. One tons may be a different ball game all together.

Too much air in the bags will make it tippy/bouncy...try starting with less rather than more. I am running just 15psi now.

Air bag psi takes some playing around with to get just right...once you do they are awesome as they are easily adjustable.

Edit; just looked at pics-it does look like you have a lift kit of some type? That may not be good...

What are you running for wheels/tires?
They look like bling wheels but hard to tell....

Bill

Do I see a lift kit on the truck?
Why did you install air bags?

pics

Also, the rear tires are at 60psi (just aired up till there was no bulge). The airbags are at 50 driver's and 60 passenger. I aired those up till I was level.

It doesn't feel like the truck is porpoising but more that the camper is. It may be normal and I'm just a worry wart.

enblethen wrote:
Which series of Happijacs? They came with the camper which was on a single rear wheel 3/4 ton megacab. Same year as mine.
Did you install the stabilizing bar?No idea what stabilizing bar you are referring to.
Are the the FT-DR2s? Don't know what that is.
Do you have the vertical ribbed front bed. Yes. The thru bolts are in the "recessed" ribs and I used my impact wrench to tighten them.
Some may not have the capacity for your camper. Siome Happijacs are only rated 2500 pounds.

I've wondered if the turnbuckles are the problem.

Which series of Happijacs? Did you install the stabilizing bar?
Are the the FT-DR2s? Do you have the vertical ribbed front bed.
Some may not have the capacity for your camper. Siome Happijacs are only rated 2500 pounds.