ICON V.S. 2.5 Piggyback Rear Shocks for 2001-Up GM 2500/3500 HD 6-8" Lift, Pair

The ICON Vehicle Dynamics V.S. 2.5 Aluminum Series Piggyback Rear Shocks (SKU 77727P, sold as a pair) are application-specific rear shocks engineered for 2001-and-up GM 2500/3500 HD trucks running 6–8 inches of lift, tuned in both length and damping for that exact platform to deliver controlled off-road performance and a composed street ride.

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Internal Bump Zone Control

A 6061 billet aluminum manifold positioned just below the shock's top cap creates an internal Bump Zone that adds 20% damping force as the shock approaches full compression. For a heavily loaded HD truck hitting rough terrain or a sharp transition at speed, that extra resistance is the difference between a controlled compression and a harsh bottom-out that rattles cargo and fatigues the chassis. The effect is built into the shock body itself, so there are no external adjusters to set or forget.

Heat Management Through Piggyback Reservoir Design

The piggyback reservoir separates the oil volume from the main shock body, giving the nitrogen-charged monotube system more fluid capacity and greater surface area to shed heat during sustained off-road use. Shock fade (the loss of damping consistency that occurs when shock oil overheats) is a real problem on long washboard runs or repeated high-speed whoops. The reservoir design keeps the 5WT shock oil in its working temperature range longer, so damping stays consistent from the first mile to the last.

Built to Be Serviced, Not Replaced

Both shocks are 100% rebuildable and 100% revalveable. When the valving no longer matches how the truck is used (heavier payload, a change in terrain, or a preference for a firmer or softer tune), the shocks can be rebuilt and revalved rather than replaced outright. Owners who want on-the-fly compression adjustment can upgrade these shocks to ICON's Compression Damping Control Valve (CDCV) configuration.

Features

• Internal Bump Zone: 6061 billet aluminum manifold adds 20% damping force near full compression to resist harsh bottom-outs
• Piggyback Reservoir: Nitrogen-charged monotube with separate reservoir for improved heat dissipation and reduced shock fade
• Application-Specific Valving: Length and damping tune configured specifically for 2001-up GM 2500/3500 HD with 6–8 inch lift
• 7/8" Hardened Shaft: Induction-hardened, chrome-plated shock shaft with PTFE-lined spherical bearings
• Bolt-On Installation: No cutting or welding required; includes application-specific mounting hardware
• Rebuildable and Revalveable: Fully serviceable; CDCV upgrade available for compression damping adjustment

Specifications

Who This Is For and Isn't

These shocks suit owners of 2001-and-up GM 2500/3500 HD trucks running 6–8 inches of rear lift who want application-tuned damping, improved heat management on sustained off-road runs, and a shock they can rebuild or revalve as their use case evolves.

These rear shocks do not fit GM 2500/3500 HD trucks with less than 6 inches or more than 8 inches of rear lift, and they are not front shocks. This listing is for the rear shock pair only and does not include front shocks, springs, control arms, or other suspension components.

Common Questions

What GM trucks do these shocks fit?

The ICON V.S. 2.5 Piggyback Rear Shocks (77727P) are engineered specifically for 2001-and-up GM 2500/3500 HD trucks with 6–8 inches of rear lift. They are not a universal fit and are not rated for lift heights outside that range.

What does the internal Bump Zone do?

The Bump Zone is created by a 6061 billet aluminum manifold inside the shock body that increases damping force by 20% as the shock nears full compression. On a heavy-duty truck, this added resistance helps prevent harsh bottom-outs during high-speed compression events without stiffening the mid-stroke ride.

Do these shocks require cutting or welding to install?

No. The ICON V.S. 2.5 Piggyback Rear Shocks are a bolt-on system that includes application-specific mounting hardware. No cutting or welding is required for installation on compatible 2001-up GM 2500/3500 HD trucks.

Can these shocks be rebuilt or retuned later?

Yes. Both shocks in the pair are 100% rebuildable and 100% revalveable, so the damping tune can be changed as payload, terrain, or preference shifts. They can also be upgraded to ICON's Compression Damping Control Valve (CDCV) configuration for on-the-fly compression adjustment.

What is included in this listing?

This listing includes two ICON V.S. 2.5 Aluminum Series piggyback reservoir rear shocks with application-specific mounting hardware. Front shocks, springs, control arms, and other suspension components are not included and must be sourced separately.