See Figure 1
The All Wheel Drive Astro van front suspension uses a rigidly mounted differential and constant velocity halfshafts. The differential remains stationary while the halfshafts move up and down to match irregularities in the road surface.
The upper and lower control arms are of the wishbone configuration as the 2 wheel drive. But, the major difference comes with the lower control arms which are sprung with torsion bars instead of coil springs. The torsion bars are mounted to the frame crossmember and are adjustable to maintain proper vehicle height.