What is the towing capacity of the GMC 3500 diesel 5th wheel?
The GMC Sierra 3500HD with the Duramax diesel can tow up to about 36,000 pounds with a fifth-wheel or gooseneck hitch, provided the truck is properly configured and loaded within its GCWR and payload limits.
Towing ratings for heavy-duty pickups are not one-size-fits-all. The exact number depends on year, trim, axle configuration, hitch type, and the specific gear and options installed on the vehicle. Here’s how to understand where that 36,000-pound figure comes from and what can affect it in real-world use.
How the rating is determined
Automakers publish maximum towing numbers that assume a fifth-wheel or gooseneck installation, the right drivetrain and chassis setup, and a payload that stays within the vehicle’s GCWR (Gross Combined Weight Rating). For the Sierra 3500HD, the highest fifth-wheel/gooseneck rating is generally cited around 36,000 pounds on properly equipped DRW (dual rear wheel) configurations. The exact figure can vary by model year and options, so always verify the rating for your specific build.
Several factors govern whether your truck can reach that top figure or sit at a lower limit in practice. A precise rating is tied to the combination of hitch type, axle setup, engine/transmission pairing, and the truck’s overall weight budget (payload plus trailer weight).
To help readers navigate these details, below are the key considerations and verification steps that can influence your official fifth-wheel towing capacity.
- Hitch type: Fifth-wheel or gooseneck connections are rated separately from bumper-pull towing, and the fifth-wheel/gooseneck rating is typically higher because of weight distribution geometry.
- Rear-axle configuration and drive type: Dual rear wheels (DRW) configurations usually offer higher towing capacities than single rear wheel setups, and 4WD vs. 2WD can affect approach/down-speed limits and braking.
- Gross Combined Weight Rating (GCWR): This is the upper limit for the total weight of the vehicle plus its load and the towed trailer; it often caps the usable tow rating for heavy trailers.
- Payload capacity: The amount of cargo, passengers, and gear the truck can carry affects how much weight can be allocated to the trailer without exceeding GCWR.
- Engine and transmission pairing: The Duramax 6.6L V8 paired with the Allison 10-speed automatic delivers the power profile that supports higher-tow configurations, but ratings still depend on the overall build.
- Model year and packages: GM updates specs with new model years and option packages, so a given number may shift slightly between releases.
In practice, achieving the full 36,000-pound limit requires the right combination of hitch, axle configuration, gearing, and payload margin. Always confirm with the manufacturer’s official spec for the exact vehicle you own or order.
How to verify the exact rating for your Sierra 3500HD
To know the precise fifth-wheel capacity for your specific truck, check these sources and steps before towing heavy loads.
- Inspect the Monroney window sticker on a new vehicle for the maximum fifth-wheel/gooseneck rating listed for that exact build.
- Review the build sheet or order codes (RPOs) to confirm drivetrain, axle ratio, and hitch-related specifications that affect rating.
- Consult the owner’s manual or the official GM spec sheets for your model year and trim to see the published fifth-wheel/gooseneck capacity.
- Ask a GMC dealer or GM Customer Assistance to confirm the rating for your VIN, especially if your configuration includes optional packages or special equipment.
Because ratings are highly specific to the vehicle’s configuration, it’s essential to verify each exact number before planning to tow a heavy fifth-wheel trailer.
Summary
In short, the GMC Sierra 3500HD with a Duramax diesel can reach a highest fifth-wheel/gooseneck towing rating near 36,000 pounds on properly configured DRW models. Real-world figures depend on hitch type, axle setup, GCWR, payload, and year-to-year spec changes. Always check your exact build documentation or consult a dealer to confirm the precise rating for your truck before towing.
