GM Suspension Decoder Z55
GM Suspension Decoder Z55
GM SUV Suspension Options: Understanding Z55 Autoride, ZW7, and More
GM’s full-size SUVs—including the Chevrolet Avalanche, Tahoe, Suburban, GMC Yukon, Yukon XL, Denali, and Cadillac Escalade—were offered with multiple suspension systems. Choosing the correct replacement shocks or suspension components depends on knowing which suspension your vehicle came with: conventional, ZW7 Premium Smooth Ride, or Z55 Autoride.
How to Identify Your GM Suspension System
Every GM vehicle has a sticker—called an RPO (Regular Production Option) label—located inside the glove box. This label lists all factory-installed options using alphanumeric codes. These RPO codes tell you exactly which suspension setup your vehicle has.
Suspension Types by RPO Code
Conventional Suspension (e.g., Z71, Z66): These use coil or torsion springs with traditional gas-charged shocks. Aftermarket shocks like the Bilstein 4600 and 5100 Series, KYB MonoMax or Gas-a-Just, Monroe Reflex, and KYB GR-2 are all compatible and popular upgrades.
ZW7 Premium Smooth Ride: This suspension uses conventional front components and Nivomat self-leveling shocks in the rear. The RPO code is ZW7. Replacing ZW7 Nivomat shocks with standard shocks requires swapping the rear springs as well to avoid sagging or poor handling.
Z55 Autoride Suspension: Identified by RPO code Z55, this system uses electronically controlled front shocks and self-leveling rear air shocks. A compressor and sensors adjust air pressure automatically based on load and road conditions.
This example shows a glove box sticker with the Z55 code, indicating the vehicle is equipped with the GM Autoride system.
Replacement Options for Z55 Autoride Suspension
Option 1: Convert to Conventional Suspension
Remove the electronic and air systems completely. Install coil springs and high-quality monotube shocks. This reduces long-term maintenance while maintaining ride comfort. Kits start around $700.
Option 2: Keep Rear Air Leveling, Remove Electronic Control
Ideal for towing. Replaces electronic shocks while maintaining air-ride rear support. Approximate cost: $870.
Option 3: Budget-Friendly Shocks with Rear Air Support
Removes electronics but keeps air ride for light towing or short-term ownership. Approximate cost: $460.
Option 4: OEM Electronic and Air Suspension Replacement
Restore full factory functionality with brand-new OEM components. Approximate cost: $1300.
Option 5: Replace Rear Shocks Only with Arnott OEM Remanufactured
For those keeping the factory air and electronic system. The Arnott AS-2708 is a remanufactured OEM rear shock with new components and a lifetime warranty. $231.70 each plus $50 refundable core charge.
Need Help Deciding?
Call us at 1-954-202-6229 and our suspension experts will walk you through the best setup for your needs, vehicle type, and driving habits.