2007-2010 Chevrolet Silverado 3500 HD II (GMT900) Extended Cab Long Box 6.0 V8 (360 Hp) SRW Automatic

The Chevrolet Silverado 3500 HD II (GMT900) Extended Cab Long Box, equipped with the 6.0-liter V8 engine producing 360 horsepower and paired with a six-speed automatic transmission, represents a significant iteration in Chevrolet’s heavy-duty truck lineage. Produced from 2007 through 2010, this variant occupied a crucial position in the Silverado 3500 HD lineup, offering a balance between capability, comfort, and affordability for buyers needing substantial towing and hauling capacity. It was part of the GMT900 generation, a substantial redesign of Chevrolet’s heavy-duty trucks, focusing on increased strength, improved interior space, and enhanced towing performance. This particular configuration, with the extended cab and long box, was a popular choice for both commercial and personal use, providing ample space for passengers and cargo.

Technical Specifications

INTRODUCTION

The Chevrolet Silverado 3500 HD II (GMT900) Extended Cab Long Box with the 6.0L V8 and automatic transmission was a workhorse designed for demanding tasks. Introduced as part of the redesigned GMT900 series in 2007, it aimed to provide a more refined and capable heavy-duty truck experience. The “II” designation signifies the second generation of the GMT900 platform, incorporating refinements based on initial feedback. This configuration slotted into the middle of the Silverado 3500 HD range, offering a step up in power and towing capacity from the base 6.0L engine with a manual transmission, but remaining more accessible than the available Duramax diesel option. The extended cab provided increased passenger space, while the long box maximized cargo-carrying ability, making it a versatile choice for contractors, farmers, and anyone needing a robust truck.

Powertrain & Engine Architecture

At the heart of this Silverado 3500 HD variant lies the Vortec LY6 6.0-liter V8 engine. This engine is a member of Chevrolet’s Vortec family, known for its robust construction and reliable performance. The LY6 features a cast iron block and aluminum cylinder heads, contributing to its durability. It utilizes a multi-port fuel injection system for precise fuel delivery and a traditional overhead valve (OHV) valvetrain. The engine produces 360 horsepower at 5400 rpm and 515 lb-ft of torque at 4200 rpm. The six-speed Hydra-Matic automatic transmission, designated 6L80E, was specifically chosen to handle the engine’s output and the truck’s substantial weight. This transmission offered smoother shifting and improved fuel economy compared to older four-speed automatics. The 6L80E features electronically controlled shifting and overdrive, optimizing performance for both towing and highway cruising.

Driving Characteristics

The 6.0L V8 and 6L80E combination delivered a capable, though not exceptionally quick, driving experience. Acceleration was adequate for everyday driving and hauling moderate loads, but the truck’s weight (approximately 5,900 lbs) was always noticeable. The automatic transmission’s gear ratios were optimized for towing, providing ample low-end torque for pulling heavy trailers. However, this also meant that the engine could feel somewhat strained when accelerating quickly at higher speeds. Compared to the manual transmission versions of the 6.0L, the automatic offered greater convenience, especially in stop-and-go traffic. It didn’t match the responsiveness of the manual, nor the sheer pulling power of the Duramax diesel, but it provided a good balance for drivers prioritizing ease of use and comfort. The suspension, tuned for heavy loads, provided a relatively comfortable ride even when unladen, though it could feel stiff over rough roads.

Equipment & Trim Levels

The Silverado 3500 HD II Extended Cab Long Box 6.0L Automatic typically came standard with features like air conditioning, power windows and locks, and an AM/FM stereo. The extended cab offered a split bench seat, providing seating for five passengers. Popular optional extras included a premium audio system, leather upholstery, power-adjustable seats, and a navigation system. Trim levels varied, with the WT (Work Truck) being the base model, offering minimal frills, and the LT (Luxury Trim) adding more comfort and convenience features. The LT trim often included features like chrome exterior accents, upgraded interior materials, and additional sound insulation.

Chassis & Braking

The Silverado 3500 HD II featured a robust chassis designed to withstand heavy loads and demanding use. The front suspension utilized an independent torsion bar setup with double wishbones, providing a comfortable ride and good handling. The rear suspension employed a traditional leaf spring design, optimized for load-carrying capacity. Braking duties were handled by ventilated disc brakes on all four wheels, with ABS (Anti-lock Braking System) as standard equipment. The front discs measured 325x38mm, while the rear discs were 325x30mm. The steering system was a cone worm with recirculation balls, providing a solid and predictable feel.

Market Reception & Comparison

The Silverado 3500 HD II 6.0L Automatic received generally positive reviews, particularly for its increased towing capacity and improved interior compared to previous generations. Critics noted that the 6.0L V8 provided sufficient power for most tasks, but it wasn’t as refined or fuel-efficient as the Duramax diesel. Compared to the diesel, the 6.0L was significantly more affordable, making it an attractive option for buyers who didn’t require the diesel’s extreme towing capabilities. Fuel economy was typical for a heavy-duty truck, averaging around 14-16 mpg in combined driving. Reliability was generally good, with the Vortec LY6 engine proving to be a durable and dependable powerplant.

Legacy

The Chevrolet Silverado 3500 HD II (GMT900) 6.0L V8 Automatic remains a popular choice in the used truck market today. The Vortec LY6 engine is known for its longevity and relatively low maintenance costs. While not as sought after as the Duramax diesel models, these trucks offer a compelling combination of capability, affordability, and reliability. Common issues include occasional oil leaks and sensor failures, but these are generally easily addressed. The GMT900 platform proved to be a successful design for Chevrolet, setting the stage for future generations of heavy-duty trucks. The 6.0L V8/automatic combination continues to be a viable option for buyers seeking a capable and dependable work truck.