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Accessory Drive Belt Guide for 1987-1996 GMC W6500 Forward Trucks

Understand the unique multi-belt system on your W6500 Forward to prevent breakdowns and keep your truck on the road.

4 minutes to read 1987-1996 GMC W6500 Forward
Difficulty
3/5
Est. Time
1.5 hrs
DIY Doable?
✅ Yes
Shop Labor
$180-$350
🚫 Do not drive — A broken belt can cause the engine to overheat or lose power steering, making the truck unsafe and risking severe engine damage.
Key Takeaways
  • Your truck uses multiple V-belts, not a single serpentine belt; confirm the quantity and size your truck needs.
  • It is best practice to replace all belts at the same time, as they have worn down together.
  • For a commercial truck, choose a premium aftermarket brand like Gates or Continental for maximum durability.
  • When replacing belts, always inspect all pulleys and tensioners for noise or wobble to prevent damage to the new belts.
The accessory drive belts on your 1987-1996 GMC W6500 Forward are critical for its operation. Unlike modern trucks that use a single serpentine belt, your vehicle uses a system of multiple individual V-belts. These belts transfer power from the engine's crankshaft to run essential components. For example, one belt might drive the alternator and water pump, while others power the power steering pump and air conditioning compressor. If any one of these belts fails, you could lose your charging system, engine cooling, or power steering, risking engine damage and leaving you stranded.

Is It Time for New Accessory Drive Belts?

On a commercial truck like the GMC W6500 Forward, uptime is everything. The accessory drive belts are fundamental wear items that require regular inspection to avoid a sudden failure. There isn't a strict mileage for replacement, but a thorough visual inspection during every oil change is a smart habit for any work truck. Paying close attention to the following warning signs is your best defense against a roadside breakdown.

Symptoms of a Bad Accessory Drive Belt

  • Squealing or Chirping Noises: A loud, high-pitched squeal, especially when starting the engine or under heavy load, is the most common sign of a worn, loose, or slipping belt. This noise should not be ignored.
  • Visible Damage: A visual check can tell you a lot. Look for cracks, frayed edges, missing rubber chunks, or a shiny, glazed surface on the sides of the belts. Any of these signs mean the belts are past their service life and need to be replaced immediately.
  • Accessory Malfunctions: If your battery warning light flickers, the engine temperature gauge climbs higher than normal, steering becomes heavy, or the A/C stops blowing cold, a belt may be slipping or broken.

Don't Mistake a Bad Pulley for a Bad Belt

Persistent noise or repeated belt failure can also be caused by a failing pulley bearing or a misaligned accessory. When you replace the belts, it is critical to spin each pulley by hand (with the engine off). They should spin smoothly and quietly. Any wobble, roughness, or grinding noise means the pulley or tensioner should be replaced to prevent it from destroying your new belts.

Choosing the Right Aftermarket Belts

For a commercial vehicle, the quality of your replacement belts matters. While OEM belts for a truck of this age may be difficult to source, top-tier aftermarket brands offer excellent performance and reliability. Given that your W6500 Forward uses multiple V-belts, it's important to identify the correct size and number of belts your specific truck requires before ordering.

Brand Quality Assessment:

  • Premium Brands (Gates, Continental): For a hard-working truck, a premium brand is a wise investment. Gates and Continental are both highly respected, OEM-quality suppliers. Gates, particularly their heavy-duty lines like FleetRunner, are designed for the high-temperature and high-mileage demands of commercial use. You can trust these brands for maximum durability.
  • Standard Brands (Dayco): Dayco is a well-known brand that offers reliable and cost-effective belts. While generally considered good quality, some mechanics prefer the materials and longevity of Gates or Continental for heavy-duty applications.

Replace Belts as a Set

Your truck has multiple accessory belts that have all been exposed to the same heat and wear. If one belt is cracked and failing, the others are likely not far behind. It is strongly recommended to replace all the accessory drive belts at the same time to ensure reliability and save on future labor.

Cost of Replacing Accessory Drive Belts on a GMC W6500 Forward

Part TypePrice Range
New Aftermarket Belts (per belt)$24.85 - $39.78
Shop Labor$180 - $350
Total Estimated Cost$250 - $500+ (depending on number of belts)

Cost estimates are for reference only and may vary based on your location, the specific needs of your truck, and the number of belts replaced.

Frequently Asked Questions (FAQ)

How many belts does my 1987-1996 GMC W6500 Forward have?

Your truck uses a V-belt system, which means it has multiple individual belts instead of one serpentine belt. The exact number, typically between 2 and 4, depends on the specific engine and accessories (like A/C) your truck is equipped with. You must confirm the number and length of the belts on your truck before ordering.

Are there any recalls for the accessory belts on this truck?

No. A search of the National Highway Traffic Safety Administration (NHTSA) database shows no recalls for the accessory drive belts on the 1987-1996 GMC W-Series trucks. Belts are considered a normal maintenance and wear-and-tear item.

Should I replace the belt tensioner at the same time?

While your truck may have some manually tensioned accessories, if it is equipped with a spring-loaded tensioner, it is highly recommended to replace it with the belts, especially on a high-mileage vehicle. The spring in the tensioner weakens over time, which can cause a new belt to slip or wear out prematurely.

Is an aftermarket belt as good as an OEM belt?

Yes, provided you choose a high-quality brand. For a commercial truck, premium aftermarket brands like Gates or Continental are reliable, cost-effective choices that meet or exceed OEM specifications for performance and durability.

Technical Specifications

System Type: Multiple V-Belts. The exact number and size of belts vary based on engine type and accessories (A/C, power steering configuration).

Wrenchy
Article researched & written by
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Meet Wrenchy → Updated Apr 19, 2026

The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.

Year Coverage
This article covers the Accessory Drive Belt for:
  • GMC W6500 Forward: 1987198819891990199119921993199419951996
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