2004 GMC T7500

Here’s a comprehensive breakdown of common issues and complaints associated with the 2004 GMC T7500, organized by category and component.

The 2004 GMC T7500 is a medium-duty truck designed for commercial applications. It offers a balance of capability and reliability, making it a popular choice for various businesses. Engine options included the Duramax diesel and Vortec gasoline engines. While owners generally appreciate its payload capacity and durability, common dislikes often involve maintenance costs and the age-related wear and tear associated with a work truck of this vintage. Engine

Duramax Diesel (6.6L)

• Fuel Injector Failure
  • Description/Symptoms: Rough idling, poor fuel economy, white or black smoke from the exhaust, and potential engine misfires. Often caused by contaminated fuel or general wear.
  • Solution: Replace the faulty fuel injector(s). May require injector calibration after installation.
  • Estimated Cost to Fix: $400 - $800+ per injector (including labor)
  • Recalls: None Found
• Glow Plug Issues
  • Description/Symptoms: Hard starting, especially in cold weather, and excessive white smoke during startup. A faulty glow plug can cause a cylinder to not fire correctly until the engine warms up.
  • Solution: Replace the faulty glow plug(s). Consider replacing all glow plugs simultaneously to ensure even performance.
  • Estimated Cost to Fix: $100 - $300+ (depending on the number of glow plugs replaced and labor)
  • Recalls: None Found

Vortec Gasoline Engine (8.1L)

• Intake Manifold Gasket Leak
  • Description/Symptoms: Coolant leak, rough idle, and potential overheating. Vacuum leak can also be present.
  • Solution: Replace the intake manifold gasket.
  • Estimated Cost to Fix: $400 - $700+
  • Recalls: None Found
• Oil Consumption Issues
  • Description/Symptoms: Excessive oil consumption, blue smoke from exhaust, and potentially fouled spark plugs. This is more prevalent on higher mileage engines.
  • Solution: Depending on the cause (worn valve stem seals, piston rings, etc.), the solution could range from valve stem seal replacement to a complete engine rebuild.
  • Estimated Cost to Fix: $500 - $5000+ (depending on the severity)
  • Recalls: None Found

Transmission

Allison 1000 Series Automatic Transmission

• Torque Converter Clutch (TCC) Failure
  • Description/Symptoms: Shuddering or vibrations at highway speeds, especially during lockup of the torque converter. Can lead to transmission overheating and eventual failure.
  • Solution: Replace the torque converter. Consider a transmission flush and filter replacement as well.
  • Estimated Cost to Fix: $800 - $2000+
  • Recalls: None Found
• Shift Solenoid Issues
  • Description/Symptoms: Erratic shifting, failure to shift into certain gears, and possible transmission error codes.
  • Solution: Replace the faulty shift solenoid(s).
  • Estimated Cost to Fix: $300 - $600+
  • Recalls: None Found

Suspension

• Leaf Spring Wear/Sagging
  • Description/Symptoms: Reduced load capacity, sagging rear end, and poor ride quality. Common due to the heavy loads these trucks often carry.
  • Solution: Replace the worn or sagging leaf springs.
  • Estimated Cost to Fix: $500 - $1500+ (depending on the number of springs replaced and labor)
  • Recalls: None Found
• Worn Ball Joints/Tie Rod Ends
  • Description/Symptoms: Loose steering, wandering on the road, and clunking noises from the front end.
  • Solution: Replace the worn ball joints and/or tie rod ends. An alignment is recommended after replacement.
  • Estimated Cost to Fix: $300 - $800+ (depending on the parts replaced and labor)
  • Recalls: None Found

Electrical

• Wiring Harness Issues
  • Description/Symptoms: Corrosion and damaged wiring, particularly in areas exposed to the elements. Can cause a variety of electrical problems, including lighting issues, sensor failures, and starting problems.
  • Solution: Repair or replace the damaged wiring harness sections. Requires careful diagnosis.
  • Estimated Cost to Fix: $200 - $1000+ (depending on the extent of the damage)
  • Recalls: None Found
• Alternator Failure
  • Description/Symptoms: Dimming lights, slow cranking, and eventual battery drain.
  • Solution: Replace the faulty alternator.
  • Estimated Cost to Fix: $200 - $500+
  • Recalls: None Found

Exterior

• Rust
  • Description/Symptoms: Rust on the frame, body panels, and undercarriage. Especially prevalent in areas with road salt.
  • Solution: Rust repair or panel replacement.
  • Estimated Cost to Fix: $100 - $1000+ (depending on the severity)
  • Recalls: None Found

Interior

• HVAC Blower Motor Failure
  • Description/Symptoms: Blower motor stops working, works intermittently, or only works on certain speeds.
  • Solution: Replace the blower motor or blower motor resistor.
  • Estimated Cost to Fix: $150 - $400+
  • Recalls: None Found
• Instrument Cluster Issues
  • Description/Symptoms: Gauges that stop working or provide inaccurate readings.
  • Solution: Repair or replace the instrument cluster.
  • Estimated Cost to Fix: $200 - $600+
  • Recalls: None Found

Summary:

The 2004 GMC T7500, while a capable work truck, is prone to several issues common in vehicles of its age and class. Engine problems (fuel injectors, oil consumption) can be costly, and transmission issues (TCC failure) are also significant. Suspension wear and electrical issues are also typical concerns. Rust is a major problem for older vehicles, which can also be costly. Depending on the severity, repairs can range from a few hundred to several thousand dollars, making a pre-purchase inspection highly recommended.