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2018 GMC Sierra 1500

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By Research the Car 4 min read

The 2018 GMC Sierra 1500 is a popular full-size pickup truck known for its comfortable ride, refined interior (especially in higher trims), and strong towing capabilities. It’s offered with a variety of engine options including a 4.3L V6 (285 hp, 305 lb-ft torque), a 5.3L V8 (355 hp, 383 lb-ft torque), and a 6.2L V8 (420 hp, 460 lb-ft torque). The 4.3L and 5.3L V8s can be paired with a 6-speed automatic transmission, while the 5.3L and 6.2L V8s can also be equipped with an 8-speed automatic. The 6.2L V8 is exclusively paired with the 8-speed transmission. Many owners appreciate the Sierra’s quiet cabin and user-friendly technology. However, some common complaints include issues with the transmission, particularly the 8-speed, and concerns about the reliability of the infotainment system. Some owners also find the fuel economy to be less than expected.

Engine

4.3L V6

  • Active Fuel Management (AFM) Lifter Failure
    • Description/Symptoms: The AFM system deactivates cylinders to improve fuel economy, but lifter failure can occur, leading to misfires, rough running, and a ticking noise. This is more prevalent in high-mileage vehicles.
    • Solution: Replacing the affected lifters, often requires removing the cylinder head. Some owners choose to delete the AFM system altogether.
    • Estimated Cost to Fix: $1,500 - $3,000+
    • Recalls: None Found

5.3L V8

  • Active Fuel Management (AFM) Lifter Failure
    • Description/Symptoms: Similar to the 4.3L V6, the AFM system can lead to lifter failure in the 5.3L V8. Symptoms include misfires, rough idling, and a noticeable ticking sound.
    • Solution: Replacing the damaged lifters is the common repair. Deleting the AFM system is also an option.
    • Estimated Cost to Fix: $1,500 - $3,000+
    • Recalls: None Found
  • Excessive Oil Consumption
    • Description/Symptoms: Some 5.3L V8 engines experience excessive oil consumption, with some owners reporting needing to add oil frequently between oil changes. This is often linked to the AFM system and piston ring design.
    • Solution: Repair options range from replacing valve cover to replacing piston rings, but sometimes engine replacement is needed for severe cases.
    • Estimated Cost to Fix: $500 - $5,000+
    • Recalls: None Found

6.2L V8

  • Active Fuel Management (AFM) Lifter Failure
    • Description/Symptoms: Like the other engines, the 6.2L V8 is prone to AFM lifter failure, resulting in misfires, rough engine operation, and unusual noises.
    • Solution: Replace failed lifters or delete the AFM system.
    • Estimated Cost to Fix: $1,500 - $3,000+
    • Recalls: None Found

Transmission

6-Speed Automatic (paired with 4.3L and some 5.3L V8s)

  • No Issues Found

8-Speed Automatic (8L90 or 8L45 - paired with 5.3L and 6.2L V8s)

  • Harsh Shifting/Shuddering
    • Description/Symptoms: Many owners report harsh shifting, shuddering, and clunking, especially during low-speed operation or when shifting between gears. This is a well-documented issue with the 8L90 and 8L45 transmissions.
    • Solution: GM issued a technical service bulletin (TSB) with a revised transmission fluid (Mobil Delvac Synthetic ATF) to address the shuddering. Other solutions involve replacing the torque converter.
    • Estimated Cost to Fix: $300 (fluid change) - $2,000+ (torque converter replacement)
    • Recalls: None Found

Suspension

  • “Chevy Shake” or Vibration at Highway Speeds
    • Description/Symptoms: Vibration felt through the steering wheel and seats at higher speeds (typically above 60 mph). This can be caused by tire imbalance, driveline issues, or suspension component problems.
    • Solution: The root cause needs to be diagnosed. Solutions include balancing the tires, replacing worn suspension components (e.g., ball joints, tie rod ends), or addressing driveline issues.
    • Estimated Cost to Fix: $100 - $1,000+ (depending on the cause)
    • Recalls: None Found

Electrical

  • Infotainment System Freezing/Crashing
    • Description/Symptoms: The infotainment system can freeze, crash, or become unresponsive. This may require a system reboot or software update.
    • Solution: Attempting a system reboot. A software update from the dealer may fix the issue. If the problem persists, module replacement might be necessary.
    • Estimated Cost to Fix: $0 (reboot) - $500+ (module replacement)
    • Recalls: None Found
  • Battery Drain Issues
    • Description/Symptoms: Some owners have experienced issues with the battery draining quickly, especially if the vehicle sits for an extended period. This can be caused by a parasitic drain from an electrical component.
    • Solution: Diagnosis involves identifying the source of the parasitic drain using a multimeter. Once identified, the faulty component needs to be repaired or replaced.
    • Estimated Cost to Fix: $100 - $500+
    • Recalls: None Found

Exterior

  • No Issues Found

Interior

  • Cracked Dashboard (Specifically in Warmer Climates)
    • Description/Symptoms: The dashboard can develop cracks, especially in areas with high sun exposure.
    • Solution: Dashboard replacement.
    • Estimated Cost to Fix: $800 - $1,500+
    • Recalls: None Found

Summary

The 2018 GMC Sierra 1500, while generally a well-regarded truck, has several common issues that potential buyers should be aware of. The most prevalent concerns are related to the Active Fuel Management system on the engines, the harsh shifting in the 8-speed automatic transmission, and electrical gremlins like infotainment system problems. The severity and cost of these issues vary. Lifter failure can be a significant expense, while a transmission fluid change might resolve some of the harsh shifting problems. Careful inspection and a pre-purchase inspection are recommended.

GMC, Sierra 1500
GMC Sierra 1500 2018
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