2018-2025 Equinox & Terrain Rear Shock Absorber: Diagnosing Bouncing, Noises, and Leaks

Symptoms of a Failing Rear Shock Absorber

A failing shock absorber will provide clear signs through changes in ride quality, noise, and visual indicators. Ignoring these symptoms can lead to reduced safety and accelerated wear on other suspension parts.

• Bouncy or Floating Ride: This is the most classic symptom. If your Equinox or Terrain continues to bounce multiple times after hitting a bump or dip, the shocks are no longer able to control the spring oscillations.
• Clunking or Knocking Noises: Worn-out mounting bushings or internal shock components can cause audible clunking or banging sounds from the rear of the vehicle, especially when driving over uneven pavement.
• Visible Fluid Leaks: The shock absorber is a sealed, oil-filled tube. If you see oily fluid or a layer of dirt-caked grime on the shock body, it means the seals have failed and the internal fluid has leaked out, rendering it useless.
• Uneven Tire Wear (Cupping): When a shock is bad, the tire can bounce off the pavement as you drive. This repeated impact can gouge out patches of rubber, creating a scalloped or "cupped" wear pattern on the tire tread.
• Rear Squat During Acceleration: If the rear of the vehicle dips excessively when you accelerate, it's a sign the shocks can't properly manage the weight transfer.
• Swaying or Body Roll in Turns: Worn shocks can make the vehicle feel unstable and lean excessively when cornering, as they can no longer control the rate of weight transfer from side to side.

Known Issues, TSBs, and Recalls

For the 2018-2024 Chevrolet Equinox and 2018-2025 GMC Terrain, there are no widespread recalls specifically targeting the rear shock absorbers. This indicates the original equipment parts are generally reliable. However, General Motors has issued a Technical Service Bulletin (TSB) that is relevant for anyone considering replacement.

TSB 18-NA-315: Replacing Shocks Individually

Contrary to the common advice to always replace shocks in pairs, GM issued a bulletin stating that modern shock absorber technology has improved. They note that many shocks returned under warranty are found to be working correctly upon inspection. The bulletin advises technicians to diagnose suspension concerns and replace only the specific shock that has failed, unless diagnostic testing confirms both have failed. While replacing in pairs is still the best practice for ensuring perfectly balanced handling, this bulletin suggests that replacing a single failed shock is an acceptable repair according to the manufacturer.

Buying a Used Rear Shock Absorber: What to Check

A low-mileage used OEM shock absorber can be a smart purchase, often providing better performance and durability than a new, budget-priced aftermarket part. An original GM shock is valved specifically for the Equinox and Terrain, ensuring the ride quality remains as the engineers intended. Here’s what to inspect before you buy.

1. Check for Leaks: This is the most important check. The outside of the shock body should be dry and clean. Any sign of oily residue, wetness, or a thick layer of grime stuck to the shock indicates a leaking seal. A leaking shock has lost its damping fluid and is no longer functional. Do not buy it.
2. Inspect the Body and Rod: Look for any major dents, deep scrapes, or bends in the main body of the shock or the chrome-plated piston rod. Significant physical damage can compromise internal function. The piston rod should be smooth and free of rust or pitting, which can tear the seals.
3. Examine the Bushings: Check the rubber bushings at the top and bottom mounting points. They should be intact, without major cracks, rot, or signs of being torn or deformed. Worn bushings can cause clunking noises.
4. Perform a Manual Bounce Test: If the shock is off the vehicle, you can test it by hand. Stand it in its normal orientation and push down on the top to compress it. It should be difficult to compress and offer smooth, consistent resistance. When you let go, it should extend back out on its own smoothly. If it compresses with little to no resistance 🎬 See how to properly diagnose failing shocks yourself. or feels jerky, it is worn out.

Replacement Overview & Difficulty

Replacing the rear shock absorbers on a 2018-2025 Equinox or Terrain is a relatively straightforward job that can be done by a DIY mechanic with basic tools.

• Difficulty: 2 out of 5
• Estimated Time: 1-2 hours for a pair
• Tools Required: Jack and jack stands, wheel chocks, socket set (specifically an 18mm socket and wrench), torque wrench.

The basic process involves safely lifting and supporting the rear of the vehicle, removing the rear wheel, supporting the lower control arm with a jack, and then unbolting the shock absorber at the top and bottom. Installation is the reverse of removal. 🎬 Watch this step-by-step replacement guide with torque specs. It is often necessary to use a jack to slightly raise or lower the suspension to align the bolt holes for the new shock.

Cost Comparison

Prices can vary based on supplier and location, but this provides a general estimate for replacing a pair of rear shocks.

OEM Part Numbers

Over the production run, GM may use several part numbers for the same component due to supplier changes or minor revisions. The following part numbers are known to fit FWD models of the 2018-2024 Chevrolet Equinox and 2018-2025 GMC Terrain. This part fits either the left or right side.

• 84157298
• 84157299
• 84230393
• 84293463
• 84361741
• 84361758
• 84865774
• 84865782
• 84912400
• 84912404
• 84912412
• 84912458

Frequently Asked Questions (FAQ)