2008 GMC Sierra 1500 Tow Specificationsby Michael G. Sanchez
The 2008 GMC Sierra 1500 full-size pickup was available in the following five body styles: regular cab with standard box, regular cab with long box, extended cab with regular box, extended cab with long box and crew cab. The Sierra's towing capacity varied depending on body style and drivetrain.
GMC offered a selection of four engines in the 2008 Sierra 1500: the Vortec 4.3-liter V-6, the Vortec 4.8-liter V-8, the Vortec 5.3-liter V-8 and the range-topping Vortec 6.0-liter V-8. The V-6 was standard on entry-level Work Truck models. The 4.8-liter V-8 was standard on SL and SLE1 trim-level Sierras. The 5.3-liter V-8 came standard on SLE2 and SLT trucks.
Three transmissions were offered: the 4L60 Hydra-Matic four-speed automatic and the heavy-duty 4L70 Hydra-Matic four-speed automatic. The 4L60 was the standard offering on all models. The 4L70 was optional on SLE1, SLE2 and SLT models. Like essentially all full-size pickups, the Sierra was available with either rear- or part-time four-wheel drive.
Equipped with the base V-6, the regular cab could be had with either a 3.23 or 3.73 rear axle. The two-wheel-drive, standard-box truck with the 3.23 axle could haul up to 4,800 pounds. With the 3.73 axle, that figure increased to 5,400 pounds. The four-wheel-drive, standard-box model came only with the 3.73 axle and had a maximum towing capacity of 5,100 pounds. The two-wheel-drive regular-cab version with the long box could haul 4,700 pounds with the 3.23 axle and 5,200 pounds with the 3.73. The four-wheel-drive model could tow a maximum of 4,900 pounds with its 3.73 rear axle.
With the 4.8-liter V-8 under its hood, the two-wheel-drive regular-cab truck with the standard box could haul 4,700 pounds with the 3.23 axle and a much improved 7,200 pounds with the 3.73 axle. The four-wheel-drive regular-cab model with the standard box had a maximum towing capacity of 6,000 pounds with its 3.42 axle. The two-wheel-drive regular-cab truck with long box could tow 5,100 pounds with the 3.23 rear axle or 7,100 pounds with the 3.73 rear axle. Finally, the four-wheel-drive regular-cab version with long box could haul 5,800 pounds with its 3.42 axle.
When outfitted with the 5.3-liter engine, the rear-wheel-drive regular-cab model with the standard box came with a 3.73 rear axle and had a maximum towing capacity of 8,200 pounds. The four-wheel-drive version featured a 4.10 rear axle and could tow up to 8,900 pounds. The rear-wheel-drive regular-cab truck with the long box had the same rear axle as the short-box model but could tow 200 pounds less. The four-wheel-drive, long-bed model had the same towing capacity as its short-bed equivalent.
The 5.3-liter V-8-powered, rear-wheel-drive extended-cab truck with the standard box was configured with a 3.73 rear axle. Its maximum towing capacity was 8,800 pounds. The four-wheel-drive version, which used the same rear axle, could haul up to 8,500 pounds. Outfitted with the optional Enhanced Trailering package, the two-wheel-drive truck could tow up to 10,300 pounds, and the four-wheel-drive model could manage an impressive 10,500 pounds. Finally, the extended-cab version with the long box could haul up to 7,500 pounds in rear-wheel-drive form with the 3.73 rear axle and 8,300 pounds with four-wheel drive and the 4.10 rear axle.
The crew cab Sierra had a maximum towing capacity of 8,700 pounds with rear-wheel drive and the 3.73 rear axle and 8,500 pounds with four-wheel drive and the same rear axle. Equipped with the optional Enhanced Trailering package, the rear-wheel-drive truck could haul up to 10,200 pounds. The enhanced four-wheel-drive model could tow an impressive maximum of 10,500 pounds, thanks largely to its 4.10 rear axle.