2001 GMC T6500

The 2001 GMC T6500 is a medium-duty truck often used for commercial applications like delivery, construction, and service vehicles. This model year offered several engine and transmission options to cater to various needs. Available engine options included the Caterpillar 3126 diesel engine, producing around 175-330 horsepower and 420-860 lb-ft of torque depending on the specific tuning. Some owners appreciate the truck’s durability and workhorse capabilities, while others find the ride quality and interior comfort lacking compared to modern vehicles. Common complaints often revolve around age-related wear and tear on components and the higher maintenance costs associated with commercial vehicles.

Engine

Caterpillar 3126 Diesel Engine

• Injector Failure
  • Description/Symptoms: Rough idling, black smoke from the exhaust, decreased fuel economy, and potential engine misfires.
  • Solution: Replacement of faulty injectors. Diagnosis should include a cylinder contribution test to identify the problematic injectors.
  • Estimated Cost to Fix: $400 - $800+ per injector replaced (parts and labor)
  • Recalls: None Found
• Turbocharger Failure
  • Description/Symptoms: Loss of power, excessive black smoke, whining or screeching noises from the engine compartment.
  • Solution: Turbocharger replacement, also inspect oil lines for blockage.
  • Estimated Cost to Fix: $1500 - $3000+ (parts and labor)
  • Recalls: None Found
• High Pressure Oil Pump (HPOP) Failure
  • Description/Symptoms: Hard starting, no starting, stalling, and low power.
  • Solution: Replace HPOP. Ensure that oil quality is adequate for HPOP lubrication.
  • Estimated Cost to Fix: $800 - $2000+ (parts and labor)
  • Recalls: None Found

Transmission

Allison Automatic Transmissions (Various Models Depending on Configuration)

• Shifting Problems/Slippage
  • Description/Symptoms: Difficulty shifting between gears, transmission slippage, harsh shifts, or failure to shift altogether. Often accompanied by diagnostic trouble codes related to transmission performance.
  • Solution: Depending on the severity, solutions range from a transmission fluid flush and filter change to a complete transmission rebuild or replacement. Valve body issues are also a common culprit.
  • Estimated Cost to Fix: $200 (fluid flush) - $5000+ (rebuild/replacement)
  • Recalls: None Found
• Torque Converter Failure
  • Description/Symptoms: Shuddering at low speeds, stalling when stopped, poor acceleration.
  • Solution: Replacement of the torque converter. Inspect the transmission for debris from the torque converter failure.
  • Estimated Cost to Fix: $800 - $2000+ (parts and labor)
  • Recalls: None Found

Suspension

• Worn Leaf Springs
  • Description/Symptoms: Sagging rear end, poor ride quality, reduced load capacity.
  • Solution: Replacement of leaf springs.
  • Estimated Cost to Fix: $500 - $1500+ per axle (parts and labor, depending on spring complexity)
  • Recalls: None Found
• Worn Shocks/Struts
  • Description/Symptoms: Bouncy ride, excessive body roll during turns, poor handling.
  • Solution: Replacement of shocks/struts.
  • Estimated Cost to Fix: $200 - $600+ per axle (parts and labor)
  • Recalls: None Found

Electrical

• Wiring Harness Issues
  • Description/Symptoms: Intermittent electrical problems, such as lights flickering, gauges not working, or starting problems. Corrosion and damaged wiring are common.
  • Solution: Inspection and repair or replacement of damaged wiring harnesses.
  • Estimated Cost to Fix: $100 - $1000+ (depending on the extent of the damage)
  • Recalls: None Found
• Alternator Failure
  • Description/Symptoms: Dimming headlights, battery warning light on, and difficulty starting.
  • Solution: Replacement of the alternator.
  • Estimated Cost to Fix: $300 - $800+ (parts and labor)
  • Recalls: None Found

Exterior

• Rust
  • Description/Symptoms: Rust on the frame, body panels, and undercarriage, especially in areas exposed to road salt.
  • Solution: Rust repair or panel replacement.
  • Estimated Cost to Fix: Varies widely depending on the extent of the rust. Could range from a few hundred dollars for minor repairs to several thousand for significant rust damage.
  • Recalls: None Found

Interior

• HVAC Issues
  • Description/Symptoms: Blower motor failure, inability to switch between heat and A/C, weak airflow.
  • Solution: Replacement of the blower motor, blend door actuator, or other faulty HVAC components.
  • Estimated Cost to Fix: $100 - $500+ (depending on the component)
  • Recalls: None Found

Summary

The 2001 GMC T6500, while a capable work truck, is prone to age-related issues, especially concerning the engine, transmission, and suspension. The Caterpillar 3126 engine can suffer from injector and HPOP failures, while the Allison transmissions are susceptible to shifting problems and torque converter issues. Electrical problems due to wiring harness degradation and rust are also common. Repair costs can vary significantly, with some issues being relatively inexpensive to fix, while others, such as major engine or transmission work, can be quite costly. Prospective buyers should carefully inspect these areas and budget for potential repairs.