2015 GMC Sierra 2500 HD
The 2015 GMC Sierra 2500 HD is a popular heavy-duty truck known for its towing capacity, comfortable ride, and available features. Engine options include the 6.0L Vortec V8 (360 hp, 380 lb-ft of torque), and the 6.6L Duramax Turbo Diesel V8 (397 hp, 765 lb-ft of torque). Both engines are paired with a 6-speed automatic transmission. Owners generally appreciate the truck’s capability and interior comfort, but some dislike its fuel economy and certain reliability issues.
Engine
6.0L Vortec V8
- Active Fuel Management (AFM) Lifter Failure
- Description/Symptoms: Engine misfires, rough idling, loss of power, and check engine light illumination. Often accompanied by excessive oil consumption. AFM lifters collapse, causing valve train issues.
- Solution: Replace all lifters with updated non-AFM lifters and perform a camshaft inspection/replacement if needed. Tuning of the ECM may be necessary.
- Estimated Cost to Fix: $2,500 - $4,000+
- Recalls: None Found
- Oil Consumption
- Description/Symptoms: Excessive oil consumption without noticeable leaks. Can lead to engine damage if not monitored and addressed.
- Solution: Replacement of valve stem seals, piston rings or in some cases a full engine rebuild. Switching to a heavier weight oil can sometimes help to slow consumption but is not a fix.
- Estimated Cost to Fix: $1,500-$6,000+
- Recalls: None Found
6.6L Duramax Turbo Diesel V8 (LML)
- CP4 Fuel Pump Failure
- Description/Symptoms: Engine stalling, difficulty starting, and metal shavings found in the fuel system. The CP4 pump is known to be less tolerant of poor fuel quality than previous Duramax fuel pumps.
- Solution: Replace the CP4 pump, fuel injectors, fuel rails, and clean the entire fuel system to remove metal contaminants. CP3 conversion kits are also an option.
- Estimated Cost to Fix: $8,000 - $12,000+
- Recalls: None Found
- Diesel Exhaust Fluid (DEF) System Issues
- Description/Symptoms: “Service Exhaust Fluid System” message, reduced engine power, and potential for the truck to enter limp mode. Issues can arise from DEF quality, sensor malfunctions, or DEF heater failures.
- Solution: Diagnose the specific issue (sensor replacement, DEF heater replacement, DEF fluid flush, etc.) and repair accordingly.
- Estimated Cost to Fix: $500 - $2,000+
- Recalls: None Found
Transmission
Allison 1000 6-Speed Automatic (Paired with 6.6L Duramax)
- Torque Converter Failure
- Description/Symptoms: Shuddering during lockup, slipping, and potentially complete transmission failure.
- Solution: Replace the torque converter, flush transmission cooler lines, and inspect transmission for internal damage.
- Estimated Cost to Fix: $2,000 - $4,000+
- Recalls: None Found
- Valve Body Issues
- Description/Symptoms: Harsh or delayed shifting, slipping between gears, and potentially complete transmission failure.
- Solution: Removal of valve body from transmission, and replace solenoid packs or the valve body as a whole.
- Estimated Cost to Fix: $1,000 - $3,000+
- Recalls: None Found
6L90 6-Speed Automatic (Paired with 6.0L Vortec)
- Torque Converter Failure
- Description/Symptoms: Shuddering during lockup, slipping, and potentially complete transmission failure.
- Solution: Replace the torque converter, flush transmission cooler lines, and inspect transmission for internal damage.
- Estimated Cost to Fix: $2,000 - $4,000+
- Recalls: None Found
- Valve Body Issues
- Description/Symptoms: Harsh or delayed shifting, slipping between gears, and potentially complete transmission failure.
- Solution: Removal of valve body from transmission, and replace solenoid packs or the valve body as a whole.
- Estimated Cost to Fix: $1,000 - $3,000+
- Recalls: None Found
Suspension
- Leaf Spring Sagging/Failure
- Description/Symptoms: Rear end sag, reduced load-carrying capacity, and potential for broken leaf springs.
- Solution: Replace leaf springs with upgraded or heavy-duty options.
- Estimated Cost to Fix: $800 - $2,000+
- Recalls: None Found
- Upper Control Arm Bushings
- Description/Symptoms: Squeaking from front suspension over bumps. Loose or imprecise steering
- Solution: Replace upper control arms
- Estimated Cost to Fix: $200-$500
- Recalls: None Found
Electrical
- Body Control Module (BCM) Issues
- Description/Symptoms: Intermittent electrical problems, including malfunctioning lights, power windows, door locks, and radio.
- Solution: Replace the BCM and reprogram it to the vehicle.
- Estimated Cost to Fix: $500 - $1,200+
- Recalls: None Found
- Radio Display Failure
- Description/Symptoms: Touchscreen becomes unresponsive, display flickers, or completely fails.
- Solution: Radio replacement.
- Estimated Cost to Fix: $300 - $1000+
- Recalls: None Found
Exterior
- Wheel Speed Sensor Failure
- Description/Symptoms: ABS light illuminated on dashboard, traction control light on, inability to engage 4 wheel drive, or difficulty braking
- Solution: Replace the wheel speed sensor.
- Estimated Cost to Fix: $100-$400
- Recalls: None Found
- Rusting around wheel wells
- Description/Symptoms: Rust forming on body panels, more common in northern climates.
- Solution: Sanding and repairing the rust, and repainting the area.
- Estimated Cost to Fix: $500+ per panel
- Recalls: None Found
Interior
- Seat Heater Failure
- Description/Symptoms: Seat heater stops working.
- Solution: Repair or replace the seat heater element.
- Estimated Cost to Fix: $200-$500
- Recalls: None Found
Summary
The 2015 GMC Sierra 2500 HD, while capable and comfortable, has some notable reliability concerns. The Duramax diesel engine’s CP4 fuel pump issue can be extremely expensive to repair. The 6.0L Vortec’s AFM lifter issues and oil consumption are also common and can be costly. Electrical issues and suspension component wear are also points to consider. The severity of these issues ranges from minor inconveniences to major repairs, with costs varying accordingly. Potential buyers should carefully inspect the vehicle’s service history and consider a pre-purchase inspection to identify any existing or potential problems.