In 2003 GM introduced a new generation of the medium-duty Kodiak/Topkick C4500/5500/6500/7500 trucks. These trucks were built under the GMT560 architecture and were used for multiple heavy-duty utility applications including buses and tow trucks. Similar to Freightliner and International trucks, the Kodiak/Topkick featured a conventional cab design that measured nearly 8 ft wide and 8 ft tall and around 20 ft long. Powering the GM Kodiak/Topkick, was a modified version of the 6.6L Duramax, that was used in Silverado/Sierra pickups. Many components in the C4500/5500 trucks were carried over and upgraded from the GM Silverado/Sierra pickups.

The 6.6L Duramax produced for the Chevy Kodiak and GMC Topkick had a lower output than the Silverado/Sierra for increased reliability. This Duramax engine had a durable foundation of a cast-iron block with aluminum heads. Internals of this engine were carried over from the Duramax used in GM Silverado/Sierra pickups. The common-rail fuel system was capable of providing these trucks with better fuel efficiency. The Bosch CP3 pump and solenoid-style injectors were at the heart of this fuel system. Fitted to this engine was a Garrett variable-geometry turbocharger that offered better performance and lower emissions. Originally, the GM Kodiak/Topkick powered by a 6.6L Duramax was paired with a 5-speed automatic transmission, but it was replaced with a 6-speed Allison automatic transmission after 2006. This generation of the 6.6L Duramax was rated at 300 hp and 605 lb-ft of torque.

The GM Kodiak/Topkick was capable of carrying 5,000 lbs. of weight in the bed and towing 14,300 lbs. which was impressive for the time. To handle that weight these trucks were supported by heavy-duty Dana 70 axles and many other robust suspension components. Production of the GM Kodiak/Topkick ended in 2009 as GM turned their focus to improving the Silverado/Sierra pickups. Parts to keep these medium-duty trucks on the road are still readily available. Perform routine maintenance on your 6.6L Duramax with the Oil Filters, Fuel Filters, and Transmission Filters at Cyberpunk Diesel. Cyberpunk Diesel offers a wide range of stock replacement and performance parts from hundreds of the top manufacturers to keep your 2003-2009 GM Duramax 6.6L Kodiak/Topkick performing at its best.