2007 GMC Sierra 1500 HD Classic

The 2007 GMC Sierra 1500 HD Classic is a full-size pickup truck known for its ruggedness and towing capability, representing the last of the GMT800 platform. It offers several engine choices, including the 6.0L Vortec Max V8 (367 hp and 375 lb-ft of torque), the 6.0L Vortec V8 (300 hp and 360 lb-ft of torque), and the 6.6L Duramax Diesel V8 (360 hp and 650 lb-ft of torque). The transmission options include the 4L80E four-speed automatic and the Allison 1000 six-speed automatic (diesel only). Owners often appreciate the truck’s reliability and simple design, but some dislike its fuel economy and dated interior.

Engine

6.0L Vortec Max V8

• Oil Consumption
  • Description/Symptoms: Excessive oil consumption, requiring frequent oil top-offs. Blue smoke may be visible from the exhaust.
  • Solution: The problem is caused by the Active Fuel Management (AFM) system. Replacing the valve cover can help with reducing oil consumption. Performing an engine flush can help, however, there is a chance the oil consumption will come back.
  • Estimated Cost to Fix: $100 - $1,000+
• Knocking Engine Noise
  • Description/Symptoms: Loud knocking or tapping noise, especially at idle or low RPMs. Often related to worn or damaged connecting rod bearings.
  • Solution: Engine rebuild or replacement. Replacing connecting rod bearings may provide a temporary solution, but engine damage is likely present.
  • Estimated Cost to Fix: $2,000 - $6,000+
  • Recalls: None Found

6.0L Vortec V8

• Oil Consumption
  • Description/Symptoms: Excessive oil consumption, requiring frequent oil top-offs. Blue smoke may be visible from the exhaust.
  • Solution: The problem is caused by the Active Fuel Management (AFM) system. Replacing the valve cover can help with reducing oil consumption. Performing an engine flush can help, however, there is a chance the oil consumption will come back.
  • Estimated Cost to Fix: $100 - $1,000+
• Knocking Engine Noise
  • Description/Symptoms: Loud knocking or tapping noise, especially at idle or low RPMs. Often related to worn or damaged connecting rod bearings.
  • Solution: Engine rebuild or replacement. Replacing connecting rod bearings may provide a temporary solution, but engine damage is likely present.
  • Estimated Cost to Fix: $2,000 - $6,000+
  • Recalls: None Found

6.6L Duramax Diesel V8 (LBZ)

• Fuel Injector Failure
  • Description/Symptoms: Rough idle, misfires, white smoke from the exhaust, decreased fuel economy, and potentially engine knocking.
  • Solution: Diagnosis of faulty injectors and replacement. It’s often recommended to replace all injectors at once.
  • Estimated Cost to Fix: $2,000 - $5,000+
  • Recalls: None Found
• Turbocharger Issues
  • Description/Symptoms: Lack of power, excessive black smoke, whistling noises from the turbocharger, and potential for turbocharger failure.
  • Solution: Inspect the turbocharger for damage or wear. Repair or replace the turbocharger, and check for boost leaks.
  • Estimated Cost to Fix: $1,000 - $4,000+
  • Recalls: None Found

Transmission

4L80E Four-Speed Automatic

• Harsh Shifting
  • Description/Symptoms: Harsh or erratic shifting between gears, especially 1st to 2nd and 2nd to 3rd.
  • Solution: Can be caused by low fluid level or a faulty shift solenoid. First, check and replace the fluid. If not, the shift solenoids will need to be replaced.
  • Estimated Cost to Fix: $50 - $500+
• Transmission Slippage
  • Description/Symptoms: Engine revs without proportional acceleration, particularly when shifting gears or under load.
  • Solution: Inspect and replace transmission fluid. If slippage continues, internal damage may require a rebuild or replacement.
  • Estimated Cost to Fix: $20 - $3,000+
  • Recalls: None Found

Allison 1000 Six-Speed Automatic

• Torque Converter Failure
  • Description/Symptoms: Shuddering or vibration during acceleration, especially when the torque converter is locking up.
  • Solution: Replace the torque converter. Address any potential underlying issues causing the failure, such as overheating.
  • Estimated Cost to Fix: $800 - $2,000+
  • Recalls: None Found
• Shift Flare
  • Description/Symptoms: RPMs increase significantly between shifts before the next gear engages.
  • Solution: Valve body issues are common, often due to wear in the valve bores. Valve body rebuild or replacement.
  • Estimated Cost to Fix: $500 - $2,000+
  • Recalls: None Found

Suspension

• Pitman Arm/Idler Arm Wear
  • Description/Symptoms: Loose steering, wandering on the road, and difficulty maintaining a straight line. Can also cause squeaking or clunking noises from the front end.
  • Solution: Replace the worn pitman arm and idler arm. Consider upgrading to heavy-duty aftermarket components for increased durability.
  • Estimated Cost to Fix: $300 - $800+
  • Recalls: None Found
• Torsion Bar Sag
  • Description/Symptoms: Front end sag, especially noticeable on heavier-duty models. Can affect ride quality and handling.
  • Solution: Adjust torsion bar keys to restore ride height. Worn torsion bars may need replacement.
  • Estimated Cost to Fix: $100 - $500+
  • Recalls: None Found

Electrical

• Instrument Panel Issues
  • Description/Symptoms: Intermittent or complete failure of the instrument panel cluster, including gauges, warning lights, and the odometer.
  • Solution: Repair or replace the instrument cluster. Repair can sometimes be done by a specialized electronics repair shop.
  • Estimated Cost to Fix: $150 - $600+
  • Recalls: None Found
• Blower Motor Resistor Failure
  • Description/Symptoms: Loss of blower motor function on certain speeds, often only working on high.
  • Solution: Replace the blower motor resistor.
  • Estimated Cost to Fix: $50 - $200+
  • Recalls: None Found

Exterior

• Rust on Rocker Panels and Cab Corners
  • Description/Symptoms: Rust developing on the lower portions of the rocker panels and cab corners.
  • Solution: Cut out the rusted metal and weld in new panels. This is often a temporary fix.
  • Estimated Cost to Fix: $500 - $2,000+

Interior

• Cracked Dashboard
  • Description/Symptoms: Cracks appearing in the dashboard, especially in warmer climates, due to sun exposure.
  • Solution: Replacing the dash is one option or adding a dash cover.
  • Estimated Cost to Fix: $100 - $1,500+

Summary

The 2007 GMC Sierra 1500 HD Classic has several common issues ranging in severity and cost. Engine and transmission problems can be costly, particularly issues with the Duramax diesel and the Allison transmission. Suspension and electrical issues are generally less expensive to address. Rust is a significant concern, especially in areas with harsh winters. Overall, prospective buyers should thoroughly inspect the vehicle and be aware of these potential problems.