Part 2: 5-Leaf Rear Springs, Shackles, U-Bolts & Shocks

Supporting the rear of the SuperCab are two 2.50-inch-wide 5-leaf rear spring packs (four main leaves plus a thick flat bottom overload leaf), riveted front frame hangers, rear swinging shackles, four high-tensile axle U-bolts with cast top plates, rubber jounce bumpers, and staggered rear telescopic shock absorbers.

Two-Stage Progressive Payload Rate: When driving with an empty bed, the truck rides smoothly on the four curved upper spring leaves while the flat bottom overload leaf sits slightly clear of the outer tips. Load 1,500 pounds of gravel or a trailer tongue into the bed, and the upper pack flattens down onto the thick bottom overload leaf—nearly doubling the effective spring rate so the truck stays level.

Why Rear Shocks Are Staggered (One Ahead, One Behind the Axle): Under hard acceleration or loose-surface braking, equal-and-opposite reaction torque from the ring-and-pinion tries to wind the leaf springs into an S-shape ("axle wrap" and wheel hop). Mounting the left shock ahead of the axle tube and the right shock behind the axle tube damps both ends of that S-windup simultaneously.