Chevrolet diesel trucks use the 6.6 liter Duramax engine, which is prone to intermittent fuel starvation, water pump failure, overheating, injector failure and injector harness chafing. These trucks also use Allison 1000 transmissions, which commonly slips into limp mode when not necessary.
The Duramax engine's design allows air to enter the fuel lines in certain conditions due to a poorly fitted O-ring inside the engine's fuel filter housing. This causes fuel starvation, which negatively affects engine performance.
Duramax engine water pumps are prone to failure after 100,000 miles of travel due to an inherent factory flaw. Overheating is common with certain models, but it is almost completely absent in others. The overheating problems typically occur when towing heavy loads in hot weather conditions.
Durmax engine injector wiring harnesses tend to chafe over time, exposing the wires. This possibly leads to difficult ignition or lack of power when attempting to start the vehicle.
The engine's Allison 1000 transmission features a limp mode safeguard that protects against catastrophic failure. When the transmission unit senses transmission slip, it locks into third gear while leaving the torque converter unlocked, which also means it no longer functions in reverse. Chevrolet owners often find that this fail safe engages in conditions when it is not necessary, such as when towing heavy loads or after making performance adjustments.