GM Suspension Codes: Z55 Autoride, ZW7, and Conventional
GM full-size SUVs can use conventional suspension, ZW7 Premium Smooth Ride, or Z55 Autoride. Before ordering shocks for an Avalanche, Tahoe, Suburban, Yukon, Yukon XL, Denali, or Escalade, identify the factory equipment and check whether a previous owner has already changed it.
Find the suspension RPO code
On the vehicles covered here, look for the Regular Production Option label inside the glove box. The alphanumeric codes identify factory-installed equipment. Use Z55 to identify factory Autoride equipment and ZW7 to identify the factory Premium Smooth Ride configuration. Inspect the current hardware too, because the label describes the original build, not necessarily what remains installed. Use the model year and exact application alongside the code rather than assuming one replacement fits every GM SUV.
Conventional suspension and ZW7 differ
Conventional configurations, including the Z71 and Z66 examples, use traditional shocks with the appropriate coil- or torsion-spring suspension. Suitable application listings may include Bilstein 4600 or 5100, KYB MonoMax or Gas-a-Just, Monroe Reflex, and KYB GR-2. ZW7 uses conventional front components with Nivomat self-leveling rear shocks in the configuration described. Replacing those Nivomat units with ordinary shocks requires compatible rear springs as well; otherwise the vehicle can sag.
Z55 repair paths
Z55 Autoride combines electronic damping with rear air-leveling equipment. One route is a complete conventional-suspension conversion using a matched kit, with separate listings for 2000–2006 and 2007–2014 vehicles. Another preserves rear air support while removing electronic control: the listed combination is Arnott SK-3062 front and AS-2700 rear. A budget-oriented air-support combination lists SK-2760 front and AS-2715 rear. P-3242 is the compressor identified alongside those options. Confirm compatibility for the exact vehicle before combining parts.
Retaining factory functions
The listed full electronic-and-air replacement option identifies Monroe 40044 front and 40034 rear. A rear-only remanufactured OEM option identifies Arnott AS-2708. Choose according to the functions you want to preserve and the condition of the remaining system. If the compressor runs excessively, inspect for leaks before replacing it. Keeping rear leveling can be useful for changing loads, but it does not increase the vehicle's towing or payload ratings.
Compare costs on the same basis
The advertised examples are approximately $700 and up for conversion, $870 for the first air-support option, $460 for the budget option, and $1,300 for full electronic-and-air replacement. AS-2708 is listed at $231.70 each plus a $50 refundable core charge and a lifetime warranty. Treat these as reference figures, not guaranteed current quotes. Check quantities, compressor inclusion, core terms, and warranty conditions before comparing totals. Call 1-954-202-6229 for help matching the repair path.
Applications and parts
Replacement Options for Z55 Autoride Suspension
Photos and diagrams
Related reading
Frequently asked questions
Can I replace ZW7 Nivomat shocks with standard shocks alone?
Not in the configuration. Compatible rear springs are also required when removing the self-leveling shocks.
Does Z55 mean I must retain electronic damping?
No. Compatible conversion paths exist, but the selected package determines whether air leveling and electronic functions remain.
