2004 GMC C5500 Topkick

The 2004 GMC C5500 Topkick is a medium-duty truck known for its robust build and workhorse capabilities. Available engine options for this year include the 6.6L Duramax LB7 diesel V8, the 8.1L Vortec gasoline V8, and the 7.8L Duramax inline-6 diesel. Transmission options included the Allison 1000 5-speed automatic and the Eaton Fuller manual transmissions. The 6.6L Duramax LB7 typically produced around 300 horsepower and 520 lb-ft of torque. Owners often praise the Topkick’s towing capacity and overall durability. Common complaints include the relatively poor fuel economy and the challenges of maneuvering such a large vehicle in tight spaces, as well as age-related issues.

Engine

6.6L Duramax LB7 Diesel

• Fuel Injector Failure
  • Description/Symptoms: LB7 engines are known for injector failures. Symptoms include excessive smoke (white or black), rough idling, decreased fuel economy, and hard starting.
  • Solution: Replace the failed fuel injectors. It’s often recommended to replace all injectors at the same time.
  • Estimated Cost to Fix: $3,000 - $8,000+ depending on shop rates and if all injectors are replaced.
  • Recalls: None Found
• Glow Plug Failure
  • Description/Symptoms: Difficulty starting in cold weather, excessive white smoke on startup, and a rough idle until the engine warms up.
  • Solution: Replace the failed glow plugs.
  • Estimated Cost to Fix: $200 - $600+
  • Recalls: None Found

8.1L Vortec Gasoline V8

• Oil Consumption
  • Description/Symptoms: Excessive oil consumption, sometimes leading to low oil levels and potential engine damage. Blue smoke from the exhaust can be a symptom.
  • Solution: Potential causes include worn valve stem seals, piston rings, or internal engine damage. Diagnosis and repair are required, which may include replacing seals, rings, or a full engine rebuild/replacement.
  • Estimated Cost to Fix: $1,000 - $5,000+ depending on the extent of the problem.
  • Recalls: None Found
• Exhaust Manifold Bolts Breaking
  • Description/Symptoms: Exhaust leak, ticking noise, especially noticeable on cold starts.
  • Solution: Replace the broken exhaust manifold bolts, and potentially the exhaust manifold itself if it is warped or cracked.
  • Estimated Cost to Fix: $400 - $1,200+
  • Recalls: None Found

7.8L Duramax Diesel Inline-6 No Issues Found

Transmission

Allison 1000 5-Speed Automatic

• Torque Converter Clutch (TCC) Failure
  • Description/Symptoms: Shuddering or vibration during torque converter lockup, slipping, or complete failure of the torque converter.
  • Solution: Replace the torque converter.
  • Estimated Cost to Fix: $1,500 - $3,000+
  • Recalls: None Found
• Shift Solenoid Failure
  • Description/Symptoms: Erratic shifting, failure to shift into certain gears, or harsh shifting.
  • Solution: Replace the faulty shift solenoid(s).
  • Estimated Cost to Fix: $300 - $800+
  • Recalls: None Found

Eaton Fuller Manual Transmission No Issues Found

Suspension

• Worn Leaf Spring Bushings
  • Description/Symptoms: Squeaking or clunking noises from the suspension, especially when going over bumps.
  • Solution: Replace the worn leaf spring bushings.
  • Estimated Cost to Fix: $200 - $600+
  • Recalls: None Found
• Ball Joint Wear
  • Description/Symptoms: Loose steering, wandering, uneven tire wear, and clunking noises from the front suspension.
  • Solution: Replace the worn ball joints.
  • Estimated Cost to Fix: $300 - $1000+
  • Recalls: None Found

Electrical

• Glow Plug Control Module Failure (Diesel Engines)
  • Description/Symptoms: Difficulty starting in cold weather, even with good glow plugs.
  • Solution: Replace the glow plug control module.
  • Estimated Cost to Fix: $200 - $500+
  • Recalls: None Found
• Wiring Harness Chafing
  • Description/Symptoms: Intermittent electrical issues, such as lights not working, sensors malfunctioning, or starting problems.
  • Solution: Inspect the wiring harness for chafing and repair or replace damaged wires.
  • Estimated Cost to Fix: Highly variable, depending on the extent of the damage. $100 - $1000+
  • Recalls: None Found

Exterior

• Rust (Cab Corners and Rocker Panels)
  • Description/Symptoms: Rust formation on cab corners, rocker panels, and other areas prone to moisture and road salt exposure.
  • Solution: Rust repair, including cutting out rusted metal and welding in new panels, followed by bodywork and painting.
  • Estimated Cost to Fix: $500 - $3,000+ depending on the severity of the rust.
  • Recalls: None Found

Interior

• Headliner Sagging
  • Description/Symptoms: The headliner material starts to detach from the backing and sag down.
  • Solution: Replace the headliner.
  • Estimated Cost to Fix: $200 - $600+
  • Recalls: None Found

Summary

The 2004 GMC C5500 Topkick is a capable truck, but age-related issues are prevalent. The most significant concerns revolve around the 6.6L Duramax LB7’s fuel injector issues, which can be very costly to repair. Other common issues include suspension wear and electrical problems. Rust is also a concern, especially in areas where road salt is used. Potential buyers should thoroughly inspect these areas and budget for potential repairs.