A self-contained pneumatic anti-sway assist vehicle body roll control system to supplement existing vehicle suspension by means of sharing load support primary and secondary volumetric gas chamber pressures for soft ride over normal, level road surfaces; then by blocking said secondary gas chambers at load side of vehicle to summarily increase spring rate within its primary load support gas chamber for increased vehicle body suspension support during lateral forces encountered with right and left turns and/or with vehicle body lean when off-camber.