My experience with chucking had to do with unloaded rear leaf Springs on a half ton pulling a light 5th wheel.
The same unit towed by a 1/4 ton Ranger was towing like a caddy.
Never felt any chucking towing heavy 5th wheels with my next two 3/4 ton trucks.
All towing has been done with the same hitch.
Unloaded springs with air bags and sloppy modern hitches will cause a cyclic vibration that will even vibrate the neck. The only way to stop it is by changing speed or with a rubber pin shock absorber to kill the vibration.
Since the first problem I opted to load my truck to the max and keep my well designed hitch that is no longer available.
Barbara and Laurent, Hartland Big Country 3500RL. 39 ft long and 15500 GVW.
2005 Ford F250 SD, XL F250 4x4, Long Box, 6.0L Diesel, 6 Speed Stick, Hypertech Max Energy for Fuel mileage of 21 MPusG empty, 12.6 MPusG pulling the BC. ScangaugeII for display..