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2008 GMC T6500

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By Research the Car 5 min read

Okay, here’s a breakdown of common issues and complaints for the 2008 GMC T6500, structured as requested. The 2008 GMC T6500 is a medium-duty truck often used for commercial applications such as box trucks, tow trucks, and utility vehicles. Engine options included the Duramax 6.6L diesel V8, producing around 300 horsepower and 520 lb-ft of torque, and the Vortec 8.1L gas V8 producing around 325 horsepower and 440 lb-ft of torque. Transmission options typically included Allison automatic transmissions. Owners often appreciate the T6500 for its durability and workhorse capabilities, while common dislikes often revolve around fuel economy, ride comfort, and the cost of maintaining a commercial-grade vehicle.

Engine

Duramax 6.6L Diesel V8 (LMM)

  • Fuel Injector Failure
    • Description/Symptoms: Hard starting, rough idling, white smoke from exhaust, decreased fuel economy, and possible engine knock. This is a common issue on the LMM Duramax.
    • Solution: Replacement of faulty fuel injectors.
    • Estimated Cost to Fix: $600 - $1200+ (depending on how many injectors need replacement and labor rates).
    • Recalls: None Found
  • EGR Cooler Failure
    • Description/Symptoms: Coolant loss, white smoke from exhaust, engine overheating. The EGR cooler is prone to cracking and leaking.
    • Solution: Replacement of the EGR cooler.
    • Estimated Cost to Fix: $400 - $800+
    • Recalls: None Found
  • Turbocharger Issues
    • Description/Symptoms: Lack of power, excessive black smoke, whistling noises from the turbo, possible check engine light with codes related to turbocharger performance.
    • Solution: Inspection of turbocharger, replacement if necessary.
    • Estimated Cost to Fix: $800 - $2500+ (depending on the extent of damage and whether a new or rebuilt turbo is used).
    • Recalls: None Found

Vortec 8.1L Gas V8

  • Exhaust Manifold Bolts Breakage
    • Description/Symptoms: Ticking noise, especially when the engine is cold, exhaust leak, decreased fuel economy. Exhaust manifold bolts are known to break on this engine.
    • Solution: Removal of broken bolts and replacement with new bolts. In some cases, the manifold may need to be resurfaced or replaced if warped.
    • Estimated Cost to Fix: $300 - $800+ (depending on the number of broken bolts and condition of the manifold).
    • Recalls: None Found
  • Oil Consumption
    • Description/Symptoms: Lowered oil level, blue smoke from exhaust.
    • Solution: Diagnosing and fixing the source of oil consumption. Depending on the cause, this may include replacing valve seals, piston rings, or the entire engine.
    • Estimated Cost to Fix: $500 - $5,000+
    • Recalls: None Found

Transmission

Allison 1000/2000 Series Automatic Transmission

  • Torque Converter Issues
    • Description/Symptoms: Shuddering, slipping, delayed engagement, or complete failure.
    • Solution: Replacement of the torque converter.
    • Estimated Cost to Fix: $800 - $2000+
    • Recalls: None Found
  • Shift Solenoid Failure
    • Description/Symptoms: Erratic shifting, harsh shifts, failure to shift, or getting stuck in a gear.
    • Solution: Replacement of faulty shift solenoids.
    • Estimated Cost to Fix: $300 - $800+
    • Recalls: None Found
  • Internal Leaks
    • Description/Symptoms: Low transmission fluid levels, slipping, and eventual transmission failure.
    • Solution: Resealing the transmission
    • Estimated Cost to Fix: $500 - $1500+
    • Recalls: None Found

Suspension

  • Leaf Spring Sagging/Failure
    • Description/Symptoms: Vehicle leaning to one side, poor ride quality, reduced load capacity. Leaf springs are prone to sagging or breaking due to the heavy loads these trucks often carry.
    • Solution: Replacement of leaf springs.
    • Estimated Cost to Fix: $500 - $1500+ per axle (depending on the complexity of the suspension and whether aftermarket springs are used).
    • Recalls: None Found
  • Worn Ball Joints/Tie Rod Ends
    • Description/Symptoms: Loose steering, clunking noises from the front end, uneven tire wear.
    • Solution: Replacement of worn ball joints and tie rod ends.
    • Estimated Cost to Fix: $300 - $1000+ per axle (depending on the extent of damage and labor rates).
    • Recalls: None Found

Electrical

  • Wiring Harness Issues
    • Description/Symptoms: Intermittent electrical problems, such as lights flickering, sensors malfunctioning, or starting issues. The wiring harnesses in these trucks can be exposed to harsh conditions and become corroded or damaged.
    • Solution: Repair or replacement of damaged sections of the wiring harness.
    • Estimated Cost to Fix: $200 - $1000+ (depending on the location and extent of the damage).
    • Recalls: None Found
  • Glow Plug Issues (Diesel Only)
    • Description/Symptoms: Hard starting, especially in cold weather, white smoke from exhaust at startup.
    • Solution: Replacement of faulty glow plugs.
    • Estimated Cost to Fix: $200 - $600+ (depending on the number of glow plugs needing replacement).
    • Recalls: None Found

Exterior

  • Rusting
    • Description/Symptoms: Rust developing on the body and undercarriage, especially in areas exposed to salt or moisture.
    • Solution: Repair of affected areas by sanding, applying rust converter, and repainting.
    • Estimated Cost to Fix: $300 - $3,000+ (depending on the severity and extent of the rust).
    • Recalls: None Found

Interior

  • HVAC Blower Motor Failure
    • Description/Symptoms: Blower motor stops working or only works on certain settings.
    • Solution: Replacement of the blower motor or blower motor resistor.
    • Estimated Cost to Fix: $150 - $400+
    • Recalls: None Found
  • Instrument Cluster Problems
    • Description/Symptoms: Gauges become inaccurate or stop working.
    • Solution: Repair or replacement of the instrument cluster
    • Estimated Cost to Fix: $200 - $800+
    • Recalls: None Found

Summary

The 2008 GMC T6500 is a capable work truck, but like all vehicles, it has its share of common issues. The most prevalent problems revolve around the Duramax diesel engine (fuel injectors, EGR cooler), the Allison transmission (torque converter, shift solenoids), suspension components (leaf springs, ball joints), and electrical systems (wiring harness corrosion). The severity of these issues ranges from relatively minor fixes to more costly repairs, with estimated costs ranging from a few hundred to several thousand dollars depending on the specific problem and the extent of the damage. Addressing these issues promptly is crucial to maintaining the reliability and longevity of the T6500.

GMC, T6500
GMC T6500 2008
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