The GMC Sierra 1500, in its first generation (GMT400), was a full-size pickup truck produced from 1988 through 1992. This generation marked a significant redesign for GMC’s truck line, offering a more modern appearance and improved features compared to its predecessors. The Regular Cab Short Wheelbase (SWB) Wideside configuration, equipped with the 5.0-liter V8 engine producing 175 horsepower and paired with a four-speed automatic transmission and four-wheel drive, represented a popular, though not top-tier, option for buyers seeking a capable and versatile work truck. It occupied a middle ground in the Sierra 1500 lineup, offering a balance between affordability and capability.
Technical Specifications
| Brand | GMC |
| Model | Sierra 1500 |
| Generation | Sierra 1500 I (GMT400) Regular cab SWB Wideside |
| Type (Engine) | 5.0 V8 (175 Hp) 4WD Automatic |
| Start of production | 1988 |
| End of production | 1992 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Pick-up |
| Seats | 3 |
| Doors | 2 |
| Fuel Type | Petrol (Gasoline) |
| Power | 175 Hp @ 4000 rpm |
| Torque | 366 Nm @ 2400 rpm / 269.95 lb.-ft. @ 2400 rpm |
| Engine layout | Front, Longitudinal |
| Number of cylinders | 8 |
| Engine configuration | V-engine |
| Cylinder Bore | 95 mm / 3.74 in. |
| Piston Stroke | 88.39 mm / 3.48 in. |
| Compression ratio | 9.3:1 |
| Fuel injection system | Single-point injection |
| Engine aspiration | Naturally aspirated engine |
| Max. weight | 2540 kg / 5599.74 lbs |
| Fuel tank capacity | 95 l / 25.1 US gal | 20.9 UK gal |
| Length | 5065 mm / 199.41 in. |
| Width | 1951 mm / 76.81 in. |
| Height | 1788 mm / 70.39 in. |
| Wheelbase | 2985 mm / 117.52 in. |
| Front overhang | 886 mm / 34.88 in. |
| Rear overhang | 1194 mm / 47.01 in. |
| Drivetrain Architecture | The Internal combustion engine (ICE) drives the rear wheels permanently, and the front wheels are driven through an electrically or mechanically operated clutch if necessary. |
| Drive wheel | All wheel drive (4×4) |
| Number of gears and type of gearbox | 4 gears, automatic transmission |
| Front suspension | Independent torsion bar, double wishbone |
| Rear suspension | Rigid axle suspension, Leaf spring |
| Front brakes | Disc |
| Rear brakes | Drum |
| Tires size | 225/75 R16 |
Powertrain & Engine Architecture
The heart of this Sierra 1500 variant was the 5.0-liter (305 cubic inch) small-block Chevrolet V8 engine. Designated as the throttle body injection (TBI) system, it was a relatively simple fuel injection setup where one or two fuel injectors were located in the throttle body. This contrasted with multi-port fuel injection, which was becoming more common in other vehicles. The engine produced 175 horsepower at 4000 rpm and 366 Nm (269.95 lb-ft) of torque at 2400 rpm. The 9.3:1 compression ratio was typical for the era, balancing performance and fuel economy. The engine’s longitudinal front-engine layout was standard for body-on-frame trucks. The four-speed automatic transmission (likely a TH700R4) was chosen for its durability and ease of use, making it a popular choice for drivers who preferred not to operate a manual transmission.
Driving Characteristics
The 175 hp V8 and four-speed automatic combination provided adequate, but not exhilarating, performance. Acceleration was modest, and the truck wasn’t designed for quick sprints. However, the engine’s torque output provided sufficient power for hauling and towing, making it suitable for its intended purpose. The automatic transmission’s gear ratios were geared towards maximizing fuel efficiency and providing smooth shifts during normal driving conditions. Compared to the available 5.7L V8, this 5.0L offered less power and acceleration. The 6.2L diesel offered significantly more torque, but at the expense of horsepower. The automatic transmission, while convenient, resulted in some power loss compared to the available manual transmissions.
Equipment & Trim Levels
The Regular Cab SWB Wideside with the 5.0L V8 and automatic transmission typically fell into the base or mid-range trim levels of the Sierra 1500 lineup. Standard features generally included a basic vinyl interior, a simple dashboard layout, and manual windows and locks. Air conditioning and an upgraded stereo system were common optional extras. The “Wideside” designation referred to the width of the bed, offering a practical cargo area for various hauling needs. Higher trim levels, such as the Sierra SLX, offered more luxurious features like cloth upholstery, power windows and locks, and a more refined interior.
Chassis & Braking
The GMT400 Sierra 1500 utilized a traditional body-on-frame construction. The front suspension consisted of an independent torsion bar setup with double wishbone components, providing a relatively comfortable ride. The rear suspension employed a rigid axle with leaf springs, which was well-suited for carrying heavy loads. The braking system featured disc brakes on the front wheels and drum brakes on the rear. This configuration was typical for trucks of this era, balancing cost and effectiveness. The 4WD system was typically a part-time system, requiring the driver to manually engage four-wheel drive when needed. Tire size was typically 225/75 R16, providing a good balance of on-road comfort and off-road capability.
Market Reception & Comparison
The GMC Sierra 1500 GMT400 was generally well-received by the market, particularly for its updated styling and improved features compared to previous generations. The 5.0L V8 with automatic transmission was considered a practical choice for buyers who prioritized affordability and ease of use over outright performance. Critics noted that the engine lacked the power of the larger V8 options, but it offered acceptable fuel economy for a full-size truck. Compared to the Ford F-150 and Chevrolet C/K series trucks, the Sierra 1500 offered a similar level of capability and features, often at a slightly higher price point, reflecting GMC’s positioning as a more premium brand.
Legacy
The GMT400 Sierra 1500, particularly the 5.0L V8 automatic variant, has become a popular choice among classic truck enthusiasts. The engine is known for its relative reliability and ease of maintenance, although the throttle body injection system can require occasional attention. Parts availability is generally good, thanks to the widespread use of Chevrolet small-block V8 engines. Today, these trucks are often found in restored condition or used as daily drivers, appreciated for their ruggedness, simplicity, and classic American truck styling. While not the most powerful or luxurious option in the Sierra 1500 lineup, the 5.0L V8 automatic represents a solid and dependable work truck that has stood the test of time.
