2008 GMC W5500HD Forward
Here’s a comprehensive breakdown of common issues and complaints for the 2008 GMC W5500HD Forward, organized by category and component.
The 2008 GMC W5500HD Forward is a medium-duty cab-over truck popular for its maneuverability and payload capacity. The primary engine option for this model year is the Isuzu 5.2L 4HK1-TC diesel engine, producing approximately 200 horsepower and 441 lb-ft of torque. A 6-speed Aisin A465 automatic transmission is the standard transmission offering. Owners often appreciate the truck’s tight turning radius and reliable diesel engine, but some dislike the cab’s basic interior and potential for rust in certain climates.
Engine
Isuzu 5.2L 4HK1-TC Diesel
- Diesel Particulate Filter (DPF) Issues
- Description/Symptoms: The DPF can become clogged, especially in applications involving frequent short trips or idling. Symptoms include reduced engine power, increased fuel consumption, and the “check engine” light illuminating. Repeated regeneration cycles may also be observed.
- Solution: Forced DPF regeneration, DPF cleaning, or DPF replacement. Ensuring the engine is reaching operating temperature during normal use and minimizing idling can help prevent issues.
- Estimated Cost to Fix: $500 - $2,500+ (depending on cleaning vs. replacement)
- Recalls: None Found
- Injector Failure
- Description/Symptoms: Common symptoms of failing injectors include rough idling, poor fuel economy, misfires, white smoke from the exhaust, and hard starting.
- Solution: Replacing the faulty injector(s) and performing a fuel system flush.
- Estimated Cost to Fix: $300 - $800+ per injector (parts and labor).
- Recalls: None Found
- Turbocharger Failure
- Description/Symptoms: Reduced power, black smoke from the exhaust, whining noises from the turbo, and potential oil leaks.
- Solution: Turbocharger replacement. Inspecting and cleaning or replacing oil lines and filters is recommended.
- Estimated Cost to Fix: $1,500 - $3,500+
- Recalls: None Found
- EGR Valve Problems
- Description/Symptoms: Rough idle, stalling, reduced power, and the “check engine” light. Carbon buildup can cause the EGR valve to stick open or closed.
- Solution: Cleaning or replacing the EGR valve. Addressing underlying causes of excessive carbon buildup is essential.
- Estimated Cost to Fix: $200 - $800+
- Recalls: None Found
Transmission
Aisin A465 6-Speed Automatic
- Harsh Shifting/Slipping
- Description/Symptoms: Abrupt or delayed shifts, slipping between gears, or a complete loss of drive.
- Solution: Diagnosis may involve checking fluid levels, inspecting the transmission for leaks, and potentially replacing the valve body or performing a complete transmission rebuild.
- Estimated Cost to Fix: $100 (fluid top off) - $4,000+ (full rebuild/replacement)
- Recalls: None Found
- Torque Converter Issues
- Description/Symptoms: Shuddering at low speeds, stalling when coming to a stop, or poor acceleration.
- Solution: Replacing the torque converter. Inspecting the transmission for related damage is recommended.
- Estimated Cost to Fix: $800 - $2,000+
- Recalls: None Found
Suspension
- Leaf Spring Sagging/Cracking
- Description/Symptoms: The truck sits lower than normal, especially when loaded. Handling may be affected. Visible cracks or breaks in the leaf springs.
- Solution: Replacing the affected leaf springs.
- Estimated Cost to Fix: $500 - $1,500+ per spring (parts and labor).
- Recalls: None Found
- Worn Shocks/Struts
- Description/Symptoms: Excessive bouncing, poor handling, and increased brake distances.
- Solution: Replacing the shocks/struts.
- Estimated Cost to Fix: $200 - $800+ (depending on parts and labor)
- Recalls: None Found
Electrical
- Wiring Harness Issues
- Description/Symptoms: Intermittent electrical problems, such as lights flickering, gauges malfunctioning, or difficulty starting. Corrosion can cause shorts and open circuits in the wiring harness.
- Solution: Locating and repairing damaged wiring. Cleaning corroded connections and applying dielectric grease. In severe cases, replacing sections of the wiring harness.
- Estimated Cost to Fix: $100 - $1,000+ (depending on the severity and location of the damage)
- Recalls: None Found
- Battery Drain
- Description/Symptoms: The battery drains overnight or within a short period, making it difficult to start the truck.
- Solution: Identifying and repairing the source of the parasitic draw (e.g., faulty relay, malfunctioning accessory). Replacing a failing battery.
- Estimated Cost to Fix: $100 - $500+
- Recalls: None Found
Exterior
- Rust
- Description/Symptoms: Rust is a common problem, especially in areas where salt is used on roads. Common areas include the cab corners, rocker panels, and frame.
- Solution: Rust repair involves removing the rust, patching the affected area, and repainting. In severe cases, frame repair or replacement may be necessary.
- Estimated Cost to Fix: $200 - $5,000+ (depending on the severity and location of the rust)
- Recalls: None Found
- Headlight/Taillight Fading or Cracking
- Description/Symptoms: Plastic headlight and taillight lenses can become faded, yellowed, or cracked over time, reducing visibility.
- Solution: Replacing the headlight or taillight assemblies.
- Estimated Cost to Fix: $100 - $500+
- Recalls: None Found
Interior
- HVAC Blower Motor Failure
- Description/Symptoms: The blower motor stops working, resulting in no airflow from the vents.
- Solution: Replacing the blower motor.
- Estimated Cost to Fix: $150 - $400+
- Recalls: None Found
- Seat Frame Cracks
- Description/Symptoms: Cracks can develop in the seat frame, especially on the driver’s side, leading to discomfort and instability.
- Solution: Welding and reinforcing the seat frame or replacing the seat.
- Estimated Cost to Fix: $100 - $500+ (welding) or $500 - $2,000+ (seat replacement)
- Recalls: None Found
Summary
The 2008 GMC W5500HD Forward, while generally reliable, can experience issues common to medium-duty diesel trucks of its age. Engine-related problems, particularly those associated with the DPF and fuel system, are potentially costly. Rust is also a concern, especially in certain regions. Transmission and suspension issues, while less frequent, can also contribute to overall maintenance costs. Potential buyers should carefully inspect the vehicle for rust, pay attention to engine performance and transmission shifting, and review maintenance records to assess the vehicle’s condition.