GMC Trucks Improved Fuel Efficiency

GMC 2012

     GMC trucks improve fuel economy Improved fuel efficiency, new aerodynamic styling and engineering improvements highlight GMC Truck Coach Division's truck lineup for 1981. Robert W. Truxell. a General Motors vice president and GMC general manager, said the 1981 models range from pickups to over-the-road tractors for virtually every trucking need. The improved fuel efficiency of 1981 GMC light-duty trucks without sacrificing load-carrying capacity results from weight reduction, engineering advancements and new aerodynamic styling. GMC conventional half-ton and ton light-duty models have weight savings ranging from 80 to 300 pounds, depending on the model.

GMC 2011

          PICKUP, Suburban and Jimmy models feature new front end sheet metal from the cowl forward. Front fenders and hood are restyled and together with a new front bumper mounted air dam improve the aerodynamics of the vehicles for greater fuel efficiency. The front and rear bumpers are made of high strength low alloy steel for additional weight savings. Grilles and headlamps are new. For 1981, a new version of the GM S.O liter (305 V8 engine is available in many light-duty GMC models up to pounds Gross Vehicle Weight Rating (GVWR) in all states except California. It features a staged four-barrel carburetor and 9.2 to 1 compression ratio for improved performance and fuel efficiency along with an "electronic spark control" or ESC system which retards engine ignition timing or audible spark knock under certain operation conditions.

GMC Front Wheel

         The front wheels freewheel until the transfer case is shifted. When torque is applied, the front wheels are automatically locked up providing traction to the front wheels for both forward and reverse operations. To return to two- wheel drive, the vehicle is stopped, shifted and driven in reverse direction about ten feet to disengage the front hubs. An optional front quad-shock pack- age is available for many GMC four- wheel-drive models. It includes an extra pair of shock absorbers on the front axle, heavy-duty rear shocks and a front axle pinion nose snubbed to limit front axle windup. Among the engineering advances are low-drag front disc brakes with a quick take up master cylinder that help con- tribute to improved fuel economy.

          The high compression 5-liter four- barrel engine with ESC is designed to deliver performance rivaling last year's 5.7-liter V8 without sacrificing the fuel economy inherent in the 5-liter engine. Fuel efficient six-cylinder engines are standard in most 1981 GMC light- duty models. A new, more convenient four- wheel-drive system is introduced in 1981 for Jimmys. Suburban’s, half- and %-ton pickup and cab-chassis models. The system combines the use of a new lightweight aluminum transfer case with automatic front locking hubs. The transfer case includes synchronizers which allow shifting into four hour.

GMC 2010

         Also, automatic transmissions for models less than pounds GVW are equipped with low spin-loss clutch plates and torque converter clutches. IMPROVED corrosion protection for '81 includes use of two-sided galvanized steel on Jimmy side panels, Suburban floor panels and van rear outer door panels. New front wheel housing to frame shields on conventional models also improve under hood corrosion protection. GMC conventional light-duty and van models have a "resume-speed" feature with optional automatic cruise control which allows the driver to return to pre- set speed automatically after braking. Standard heaters have new four-position fan control including an "off" position to eliminate automatic air flow when the ignition switch is turned on pickups. Jimmys and Sub urban feature a restyled instrument panel that includes new pad, instrument cluster bezels, international symbols for the controls and new stereo radio speakers.

GMC 2009

        Tinted glass is standard for Jimmy and Suburban models and pickups have a full foam front bench seat with inertia-type folding seat back. The GM 5.7-liter V8 diesel is again available in the two-wheel drive half-ton GMC pickup. A 2.73 rear axle with GVWR and standard metric radial tires helps improve the economy of the diesel pickup. FOR '81, a new heavy-duty one-ton, two-wheel-drive cab-chassis model is offered. It features heavy-duty rear springs and front suspension, including rated air bag auxiliary front springs. Caballero, which combines the features of both a passenger car and a pickup, has a new horizontal grille for 1981 along with new headlamp bezels, wheel covers and styled instrument panel.