Those springs look pretty normal from what I remember of my stockers.

Do you have a video camera? You could strap it to the frame under the truck pointed at the axle and then drive in the situations where the problem occurs, and then verify if the axle wrap is indeed the cause. I've thought of doing this myself, but never gotten around to it.

'97 4Runner, '06 F350, '86 4Runner, '05 WR450
http://home.4x4wire.com/erik