Sway with new truck

Hitch head adjuatment and or tires.
A hitch head that is not at the correct angle because the new truck is a bit higher or lower will create problems. Also tires can cause all sorts of problems.

Also make sure your truck's tires aren't over-inflated. Some shops and dealers still put tires at max sidewall, instead of the door sticker pressure. Too much pressure reduces your contact patch. TPMS only alarms if its low or too hot.

At first look, the trailer actually appeared to be a bit nose-down on the new truck, so I was considering raising it a notch. Perhaps that is not a good idea if a bit nose down is preferable to a bit nose high.

Your new truck may sit higher than the old one and be causing your trailer to tow with the nose high. You might have to lower the hitch head on your shank one hole to compensate. Towing nose high tends to cause a trailer to be less stable in many cases. Check to see that your trailer is level or slightly nose down. If not, adjust your hitch.

Another cause of the different towing action may be the new tires on the new truck. Often, new tires are "squirmy" which causes weird towing feelings and will settle down once the newness wears off. Check tire pressures also.
Barney

Tongue weight is always the first thing I consider - however, nothing has changed as far as the weight distribution of the trailer and it pulled fine with the old truck.

I would verify the tongue weight of the camper is up in the 12 to 13% or higher per the GVW of the camper.

And, if you changed trucks, did you totally reset the WD hitch for proper weight distribution (WD) on the truck and then adjust the hitch up and down to level out the camper?

If the WD is all wrong and the camper is nose high, it can affect the towing. Depending on the actual camper, some lose tongue weight when a lot of nose high. And on some, nose high can create wind currents at the top front of the camper that can cause unstable towing.

Hope this helps

John

Did you re-adjust the hitch for the possibly higher truck height? Probably did, but it was my first thought with all other things being the same.

I found that tongue weight seems to make a big difference with regards to that. I added some gear to my forward storage bay and all is well even with big rigs going by.

Not enough tongue weight? Do you have a large load behind the axles causing your tongue weight to be to light?