Parts for your 2018 Holden Commodore-Gas struts

2018 Holden Commodore gas struts — what they do and when to replace them

Based on technical references, gas struts are absolutely relevant to the 2018 Holden Commodore (ZB). The Holden ZB Owner’s Manual and GM/Opel Insignia B service literature specify gas‑pressurised support struts on the rear liftgate (Liftback) and tailgate (Sportwagon/Tourer). Most ZB variants use a manual prop rod for the bonnet rather than gas struts, which those same sources note. GM’s electronic parts catalogue for ZB also lists rear compartment/tailgate strut assemblies by body style. So, for the 2018 Commodore’s rear opening, gas struts are fitted and do the heavy lifting.

On the 2018 Commodore, these struts counterbalance the weight of the liftback or wagon tailgate so it opens smoothly, stays put, and doesn’t crash down. They’re sealed, nitrogen‑charged dampers designed for years of daily use, but like any wear item they gradually lose pressure. Cold mornings, high cycling, and grit on the shaft speed up that fade.

As part of routine servicing, it pays to check the gas struts quickly:

• Open the tailgate and feel for weak lift, slow rise, or any sag mid‑stroke.
• Look for oily misting or dirt rings on the shaft — signs the internal seal’s passing.
• Listen for creaks at the ball sockets, that’s usually dry pivots, not the gas charge.

If replacement’s due, best practice is to change them in pairs to keep even support. Match body style (Liftback vs Sportwagon/Tourer) and rating, the force is marked in newtons (N) on the strut label. Avoid generic lengths or “near enough” forces — the tailgate geometry on the ZB is sensitive to spec. During the job, always support the tailgate with a prop or a helper. Pop the metal retaining clips with a small flat screwdriver, swap the struts, then ensure the clips are fully seated. Don’t grease the chrome shaft — it attracts grit and chews seals — but a dab of suitable lubricant on the ball studs is fine.

Most owners notice end‑of‑life somewhere around the five‑to‑eight‑year mark, sooner if the car lives outdoors. A fresh set restores the easy, one‑handed lift Commodore drivers expect, and prevents surprise drops that can stress hinges, trims, or a power tailgate motor where fitted.

How can someone tell if their 2018 Commodore’s gas struts are failing?

Common clues include a tailgate that won’t stay up in cooler weather, rises very slowly, or drops the last part of travel. Oily residue on the strut body or a dirty ring on the shaft points to a leaking seal. If one side looks fine but the tailgate twists when lifting, both struts are still due — they work as a pair.

Do both gas struts need replacing at the same time?

Yes. Even if only one feels weak, replacing both keeps the lift and hold balanced, protects hinges, and ensures the new strut isn’t overworked by an older partner. It’s a small extra cost that usually saves headaches.

What spec struts does a 2018 Commodore need?

Spec depends on body style (Liftback vs Sportwagon/Tourer) and optioned tailgate system. Use the VIN with a parts lookup or read the force rating (in newtons) and length off the original strut label. Matching OE length, end fittings, and force is key to proper lift and latch alignment.