2005 GMC W5500HD Forward

The 2005 GMC W5500HD Forward is a medium-duty cab-over truck designed for commercial applications. In 2005, the most common engine option was the Isuzu 4HK1-TC 5.2L inline-4 diesel engine, producing around 200 horsepower and 441 lb-ft of torque. Some owners appreciate the truck’s maneuverability in tight spaces and its good visibility. However, some common dislikes include the rough ride and potential for higher maintenance costs compared to lighter-duty trucks. Other engine options included the Isuzu 4HE1-TC 4.8L inline-4 diesel, with slightly lower horsepower and torque, and the Isuzu 6HK1-TC 7.8L inline-6 diesel, offering higher horsepower and torque. The Aisin A465 6-speed automatic transmission was the common transmission option.

Engine

Isuzu 4HK1-TC 5.2L Diesel

• Injector Failure
  • Description/Symptoms: Difficulty starting, rough idling, white smoke from the exhaust, reduced power, and poor fuel economy.
  • Solution: Replacement of faulty injectors. It’s recommended to replace all injectors at the same time to ensure balanced performance.
  • Estimated Cost to Fix: $800 - $2000+ depending on how many injectors are replaced.
  • Recalls: None Found
• EGR Valve Clogging
  • Description/Symptoms: Reduced engine power, rough idle, poor fuel economy, and the check engine light illuminating.
  • Solution: Cleaning or replacing the EGR valve. Ensuring the engine’s air intake system is clean can help prevent future clogging.
  • Estimated Cost to Fix: $200 - $600+
  • Recalls: None Found

Isuzu 4HE1-TC 4.8L Diesel

No Issues Found

Isuzu 6HK1-TC 7.8L Diesel

No Issues Found

Transmission

Aisin A465 6-Speed Automatic

• Shift Solenoid Failure
  • Description/Symptoms: Harsh or erratic shifting, failure to shift into certain gears, slipping, or complete loss of drive.
  • Solution: Replacing the faulty shift solenoid(s). Transmission fluid flush and filter replacement are recommended after the repair.
  • Estimated Cost to Fix: $400 - $1000+
  • Recalls: None Found
• Torque Converter Failure
  • Description/Symptoms: Shuddering or vibration, especially during acceleration, poor fuel economy, overheating, and transmission slipping.
  • Solution: Replacement of the torque converter. Checking the transmission fluid for signs of contamination is crucial to identify the root cause.
  • Estimated Cost to Fix: $800 - $2500+
  • Recalls: None Found

Suspension

• Leaf Spring Sagging/Cracking
  • Description/Symptoms: Reduced ride height, poor handling, uneven tire wear, and a noticeable lean to one side.
  • Solution: Replacement of the leaf springs. Upgrading to heavy-duty springs can provide better support, especially when frequently hauling heavy loads.
  • Estimated Cost to Fix: $500 - $1500+ per axle
  • Recalls: None Found
• Worn Shock Absorbers
  • Description/Symptoms: Bouncy ride, excessive body roll during turns, poor handling, and increased stopping distance.
  • Solution: Replacement of shock absorbers. Upgrading to heavy-duty shocks can improve ride quality and handling, especially with a loaded vehicle.
  • Estimated Cost to Fix: $200 - $600+ per axle
  • Recalls: None Found

Electrical

• Wiring Harness Issues
  • Description/Symptoms: Intermittent electrical problems, such as lights flickering, sensors malfunctioning, or difficulty starting.
  • Solution: Inspect the wiring harness for damage, corrosion, or loose connections. Repair or replace damaged sections of the harness. Applying dielectric grease to connections can help prevent future corrosion.
  • Estimated Cost to Fix: $200 - $1000+ depending on the extent of the damage
  • Recalls: None Found
• Alternator Failure
  • Description/Symptoms: Dimming headlights, a warning light on the dashboard, a dead battery, or difficulty starting the vehicle.
  • Solution: Replacing the alternator. Inspecting the battery and charging system components is important to ensure proper function.
  • Estimated Cost to Fix: $300 - $800+
  • Recalls: None Found

Exterior

• Rust on Cab Corners and Wheel Arches
  • Description/Symptoms: Visible rust on the lower cab corners and wheel arches, particularly in areas exposed to road salt and moisture.
  • Solution: Removing the rust, repairing damaged metal, and applying rust-resistant paint or coating.
  • Estimated Cost to Fix: $300 - $1000+ per area
  • Recalls: None Found

Interior

• HVAC Blower Motor Failure
  • Description/Symptoms: The blower motor stops working or only works on certain settings, resulting in no air or weak airflow from the vents.
  • Solution: Replacing the blower motor. Inspecting the blower motor resistor is recommended as well since it often fails along with the motor.
  • Estimated Cost to Fix: $150 - $400+
  • Recalls: None Found

Summary

The 2005 GMC W5500HD Forward, equipped with the Isuzu 4HK1-TC 5.2L diesel engine, is susceptible to injector failure and EGR valve clogging, impacting performance and potentially requiring costly repairs. The Aisin A465 transmission may experience shift solenoid or torque converter issues. Suspension components such as leaf springs and shocks can wear out, leading to handling problems. Electrical issues such as wiring harness problems and alternator failure could occur. Rust is a potential concern, particularly on the cab corners and wheel arches. Blower motor failure is also possible, affecting climate control. While some of the repairs can be relatively inexpensive, engine and transmission repairs can be more costly, making it crucial to inspect these components thoroughly before purchasing a used model.