GMC Sierra Owners Manual
Adding a Snow Plow or Similar Equipment
Before installing a snow plow on the vehicle, here are some things you need to know:
Notice: If the vehicle does not have the snow plow prep package, adding a plow can damage the vehicle, and the repairs would not be covered by warranty. Unless the vehicle was built to carry a snow plow, do not add one to the vehicle. If the vehicle has the snow plow prep package, called RPO VYU, then the payload the vehicle can carry will be reduced when a snow plow is installed. The vehicle can be damaged if either the front or rear axle ratings or the Gross Vehicle Weight (GVW) are exceeded.
Some vehicles are built with a special snow plow prep package, called RPO VYU. If the vehicle has this option, you can add a plow to it, provided certain weights, such as the weights on the vehicle's axles and the Gross Vehicle Weight (GVW), are not exceeded.
The plow the vehicle can carry depends on many things, such as:
• The options the vehicle came with, and the weight of those options.
• The weight and number of passengers intended to be carried.
• The weight of items added to the vehicle, like a tool box or truck cap.
• The total weight of any additional cargo intended to be carried.
Say, for example, you have a 318 kg (700 lb) snow plow. The total weight of all occupants and cargo inside the cab should not exceed 135 kg (300 lb). This means that you may only be able to carry one passenger. But, even this may be too much if there is other equipment already adding to the weight of the vehicle.
Here are some guidelines for safely carrying a snow plow on the vehicle:
• Make sure the weight on the front and rear axles does not exceed the axle rating for each.
• For the front axle, if more cargo or passengers must be carried, appropriate counter ballast must be installed rear of the rear axle.
Counter ballast must be properly secured so it will not move during driving.
• Follow the snow plow manufacturer's recommendations regarding rear ballast. Rear ballast may be required to ensure a proper front and rear weight distribution ratio, even though the actual weight at the front axle may be less than the front axle rating.
• The snow plow manufacturer or installer can assist you in determining the amount of rear ballast required, to help make sure the snowplow/vehicle combination does not exceed the GVW rating, the front and rear axle ratings, and the front and rear weight distribution ratio.
• The total vehicle must not exceed the GVW rating.
Front axle reserve capacity is the difference between the Gross Axle Weight Rating (GAWR) and the front axle weight of the vehicle with full fuel and passengers. Basically, it is the amount of weight that can be added to the front axle before reaching the front GAWR.
The front axle reserve capacity for the vehicle can be found in the lower right corner of the Certification/Tire label, as shown.
In order to calculate the amount of weight any front accessory, such as a snow plow, is adding to the front axle, use the following formula:
(W x (A +W.B.)) /W.B.= Weight the accessory is adding to the front axle.
W = Weight of added accessory
A = Distance that the accessory is in front of the front axle
W.B. = Vehicle Wheelbase
For example, adding a 318 kg (700 lb) snow plow actually adds more than 318 kg (700 lb) to the front axle. Using the formula, if the snow plow is 122 cm (4 ft) in front of the front axle and the wheel base is 305 cm (10 ft), then:
W = 318 kg (700 lb)
A = 122 cm (4 ft)
W.B. = 305 cm (10 ft)
(W x (A +W.B.))/W.B. = (318 x (122 + 305))/305 = 445 kg (980 lbs)
So, if the front axle reserve capacity is more than 445 kg (980 lbs), the snow plow could be added without exceeding the front GAWR.
Heavier equipment can be added on the front of the vehicle if it is compensated for by carrying fewer passengers, less cargo, or by positioning cargo toward the rear.
This has the effect of reducing the load on the front. However, the front GAWR, rear GAWR, and the Gross Vehicle Weight Rating (GVWR) must never be exceeded.
On some vehicles that have certain front mounted equipment, such as a snow plow, it may be possible to load the front axle to the front gross axle weight rating (GAWR) but not have enough weight on the rear axle to have proper braking performance. If the brakes cannot work properly, you could have a crash. To help the brakes work properly when a snow plow is installed, always follow the snow plow manufacturer or installer's recommendation for rear ballast to ensure a proper front and rear weight distribution ratio, even though the actual front weight may be less than the front GAWR, and the total vehicle weight is less than the gross vehicle weight rating (GVWR).
Maintaining a proper front and rear weight distribution ratio is necessary to provide proper braking performance.
Total vehicle reserve capacity is the difference between the GVWR and the weight of the truck with full fuel and passengers. It is the amount of weight that can be added to the vehicle before reaching the GVWR.
Keep in mind that reserve capacity numbers are intended as a guide when selecting the amount of equipment or cargo the truck can carry. If unsure of the vehicle's front, rear, or total weight, go to a weigh station and weigh the vehicle. Your dealer can also help with this.
The total vehicle reserve capacity for the vehicle can be found in the lower right corner of the Certification/Tire label as shown previously.
See your dealer for additional advice and information about using a snow plow on the vehicle. Also, see Vehicle Load Limits on page 9‑17.
Emergency Roof Lamp Provisions
Vehicles with the RPO VYU snow plow prep package also have an emergency roof lamp provision package, RPO TRW. Wiring for the emergency roof lamp is provided above the overhead console. See Auxiliary Roof-Mounted Lamp on page 6‑7 for switch location.