2016 Chevrolet Silverado 3500HD Transmission & Axle Gear Ratios

The 2016 Chevrolet Silverado 3500HD is a heavy-duty workhorse designed to handle massive payloads and extreme towing demands. To achieve this, Chevrolet paired its powerful 6.0L Vortec V8 gasoline engine and the legendary 6.6L Duramax V8 turbo-diesel with heavy-duty transmissions and robust rear axle configurations. Understanding your truck's specific transmission and axle gear ratios is crucial for maximizing towing efficiency, optimizing fuel economy, or diagnosing drivetrain issues.

Here is a comprehensive breakdown of the transmission and axle gear ratios for the 2016 Chevrolet Silverado 3500HD.

Transmission gear ratios

For the 2016 model year, the Silverado 3500HD was equipped with one of two 6-speed automatic transmissions, depending on the engine choice. The gasoline engine was paired with GM's heavy-duty 6L90, while the Duramax diesel was mated to the renowned Allison 1000 transmission.

6L90 6-Speed Automatic (Paired with 6.0L Vortec V8 Gas)

The 6L90 features a deep first gear for getting heavy loads moving off the line, with two overdrive gears for highway cruising.

Allison 1000 6-Speed Automatic (Paired with 6.6L Duramax V8 Diesel)

The Allison 1000 is overbuilt to handle the immense 765 lb-ft of torque produced by the Duramax. It features slightly taller lower gears compared to the 6L90, relying on the diesel's low-end torque to get loads moving.

Available axle ratios

Because the 3500HD is strictly a heavy-duty truck, Chevrolet kept the axle ratio options simple and optimized for maximum capability.

Note: Most 2016 Silverado 3500HD models are also equipped with the G80 heavy-duty automatic locking rear differential (Eaton Locker).

How to identify your axle ratio

The easiest and most accurate way to identify the factory axle ratio on your 2016 Chevrolet Silverado 3500HD is by checking the Regular Production Option (RPO) codes.

1. Locate the Service Parts Identification (SPID) sticker. On 2016 Silverados, this sticker is typically found inside the glove box door.
2. Scan the three-character codes. Look for codes starting with "G".
3. Decode the RPO:
   • GT4: Indicates a 3.73 axle ratio.
   • GT5: Indicates a 4.10 axle ratio.
   • G80: Indicates the presence of the automatic locking rear differential.

If the sticker is missing or unreadable, you can also use a GM-specific VIN decoder online, or contact a local dealership parts department with your VIN to request a build sheet.

Towing vs MPG impact

When it comes to axle ratios, there is always a trade-off between pulling power and fuel economy.

• Numerically higher ratios (e.g., 4.10): Often referred to as "shorter" or "lower" gearing, a 4.10 ratio allows the engine to rev higher at a given speed. This multiplies torque to the wheels, making it vastly superior for towing heavy fifth-wheel trailers, hauling massive payloads, or driving in steep mountainous terrain. The downside is reduced highway fuel economy and higher cruising RPMs.
• Numerically lower ratios (e.g., 3.73): Often called "taller" gearing. While 3.73 is still heavily geared for a truck, in the context of the 3500HD (paired with the torque-monster Duramax), it acts as the perfect middle ground. It provides more than enough mechanical leverage to tow at the truck's maximum rating while keeping RPMs low on the highway to conserve diesel fuel.

Common issues

The driveline components in the 2016 Silverado 3500HD are incredibly robust, but they are not entirely immune to wear and tear, especially given the grueling conditions these trucks are subjected to.

• Ring & pinion whine: Often caused by improper backlash settings, worn carrier bearings, or low differential fluid. If you hear a high-pitched whine that changes pitch depending on whether you are accelerating or coasting, the ring and pinion gears may be worn.
• G80 Locker engagement clunks: The Eaton G80 automatic locking differential relies on a flyweight governor mechanism. As the truck ages, the engagement can become harsh or clunky. Severe abuse (like aggressive burnouts or rock crawling) can cause the locker mechanism to shear or shatter.
• Carrier bearing wear: On 3500HD models with a two-piece driveshaft (common on Crew Cab Long Box models), the center support bearing (carrier bearing) can wear out, causing a shudder or vibration during take-off or acceleration.

If you suspect your truck is suffering from worn gears, failing bearings, or transmission slipping, it is highly recommended to have a professional diagnose and rebuild the driveline components.

Find a driveline shop on Repairius to get your Silverado 3500HD back on the road and ready to haul.