Not specifically F-series related, but happened while I was riding with a buddy in his '96 Explorer the other day, and wondered if anyone had an idea.

Driving down the highway, he goes to change lanes around 65-70 mph range, and as he begins to turn the wheel, the truck starts to undulate/sway/rock side-to-side. So he stops the lane change and the truck settles back down. It only seemed to happen on a left-to-right change, not a right-to-left. Kinda weird. We stop to look if anything was obviously loose underneath, but saw nothing. Any ideas??

Chris

 

Bad section of road.
Low tire pressure.
Worn shock absorber.
Unbalance load.
Any combination of above.