Signs Your Liftgate Lift Support Is Failing

A liftgate lift support that is beginning to fail will show itself through difficulty opening the hatch, sagging when raised, or unexpected closing. Recognizing these symptoms early helps you avoid being stuck with a liftgate that won't stay open, prevents potential injury from a falling hatch, and keeps cargo access safe and reliable. Left unaddressed, a weakened lift support can eventually fail completely, leaving you unable to open your liftgate safely.

What Does a Liftgate Lift Support Do?

A liftgate lift support, commonly called a gas strut or lift cylinder, is a hydraulic component filled with pressurized nitrogen gas and oil that holds your liftgate or hatchback in the open position and assists in smooth opening and closing. It works similarly to the struts in your vehicle's suspension, but smaller and mounted vertically on either side of the liftgate frame. When you push up on the liftgate, the gas inside the strut expands and provides upward force; when you pull down to close it, the internal valves control the descent so the liftgate closes smoothly rather than slamming shut. Over time, the internal seals degrade and pressure is lost, reducing the strut's ability to support the weight of the liftgate.

Common Signs of a Failing Liftgate Lift Support

• Liftgate Sags or Won't Stay Open — The most obvious sign is that your liftgate no longer stays at the height you raise it to, instead slowly sagging down on its own. This happens because the gas pressure inside the strut has dropped below the threshold needed to counteract the weight of the liftgate.
• Difficult or Impossible to Open — You find yourself struggling to push the liftgate up, or it won't open at all without excessive force. This indicates one or both lift supports have lost sufficient pressure to assist the opening motion.
• Jerky or Uneven Opening Motion — Instead of smooth, fluid motion, the liftgate opens or closes in stops and starts, or one side opens faster than the other. This often signals that one strut is failing faster than the other, creating uneven support.
• Hissing or Popping Sounds — You hear audible hissing or popping noises coming from the lift supports when opening or closing the liftgate. These sounds indicate gas is escaping through a failed seal or the internal pressure is fluctuating abnormally.
• Visible Leaks or Damage — You notice oily fluid seeping from around the base of the strut rod, corrosion on the cylinder body, a bent rod, or visible cracks in the outer casing. Any of these signs indicates the strut has failed internally and is losing its pressurized fluid.
• One Support Noticeably Weaker Than the Other — When you gently press down on the open liftgate, it resists more on one side than the other, or one side appears lower. This asymmetry suggests one strut is significantly degraded while the other still has some pressure remaining.

What Causes Liftgate Lift Support Failure?

• Normal Wear and Tear — Liftgate lift supports are designed to open and close thousands of times over the life of your vehicle. Each cycle puts stress on the internal seals, and eventually, those seals degrade and no longer hold pressure, causing the strut to fail.
• Loss of Internal Pressure — The nitrogen gas inside the strut slowly leaks out through microscopic imperfections in seals or welds. Once pressure drops below a certain point, the strut can no longer support the liftgate weight or assist in opening.
• Environmental Damage — Exposure to road salt, moisture, extreme temperature changes, and UV radiation causes corrosion and degradation of the external casing and seals. This is especially common in coastal areas or climates with harsh winters where salt is used on roads.
• Manufacturing Defects or Poor Installation — Occasionally, a lift support leaves the factory with a defective seal or internal component, causing premature failure. Improper installation or damage during installation can also reduce the strut's lifespan.

Can You Drive With a Bad Liftgate Lift Support?

While a failing lift support won't prevent your vehicle from running or you from driving it, it creates significant safety hazards and reduces convenience. A weakened or failed strut means your liftgate may close unexpectedly and strike you, a passenger, or someone standing nearby—especially if you're loading or unloading cargo. You'll also struggle to access your trunk or cargo area, and the uncontrolled descent of a heavy liftgate poses a genuine injury risk. For these reasons, you should avoid using the liftgate until the supports are inspected and replaced. Because a falling liftgate can cause injury and this repair involves pressurized components and potential for pinch injuries, it is strongly recommended that you have a qualified mechanic inspect and replace the lift supports if you are not experienced with this type of repair. Attempting this work without proper knowledge, tools, and safety precautions could result in personal injury.

How to Diagnose a Faulty Liftgate Lift Support

1. Open the liftgate fully and release your hand—observe whether it remains in the raised position or begins to sag downward over a few seconds. A properly functioning support should hold the liftgate at the open position indefinitely.
2. Test the opening and closing speed and listen carefully for any unusual sounds. Normal operation should be smooth and quiet; hissing, popping, or grinding noises are red flags indicating internal failure or gas escape.
3. Visually inspect both lift supports along their full length for visible leaks (oily residue), surface corrosion, bent rods, cracks in the cylinder body, or any other physical damage. Compare the appearance of both sides—asymmetrical damage or wear suggests uneven failure.
4. Gently press downward on the open liftgate and feel the resistance from the lift supports. Push harder to test whether one side feels significantly weaker than the other, which indicates uneven support and uneven wear between the two struts.
5. These diagnostic steps are general guidance, and specific procedures, tools, safety precautions, and vehicle-specific details vary by make and model. Always consult your vehicle's service manual for detailed diagnostic and repair instructions, and prioritize your safety when working near a moving or heavy liftgate component.

Liftgate Lift Support Replacement Cost

Replacement lift supports typically cost between $60–$200 per support for the parts themselves, depending on your vehicle type and whether you choose an OEM or aftermarket equivalent. Labor costs for professional installation generally range from $150–$400, though this varies based on vehicle design, engine bay layout, and regional shop rates. For example, most Toyota, Honda, Ford, and Chevrolet sedans and crossovers fall into the mid-range category, while diesel pickup trucks or vehicles with tighter undercarriage designs may approach the higher end. Many shops recommend replacing both lift supports at the same time rather than one at a time, since the remaining strut will likely fail soon after, especially on higher-mileage vehicles. Total out-of-pocket cost for a professional two-strut replacement typically falls between $300–$600 for most domestic vehicles, but always request a written estimate from your mechanic before authorizing work.