Brand new 2500hd pickup with brand new tires. Are they an aggressive tread pattern? Tread squirm can cause problems even not towing. Just another thought.
On our last trip to north Florida it was a windy day. I have no sway control on our hitch. The wind pushed us around a bit. Every rig that passed us or we passed had sway control. They were being blown around as well. Nothing drastic but some sway with passing trucks or crosswinds is inevitable. If it straightens out after the push, you're probably ok on tongue weight and alignment.
