2017 Volvo VNL Transmission & Axle Gear Ratios

The 2017 Volvo VNL is one of the most prominent Class 8 heavy-duty trucks on the highway, renowned for its driver comfort, aerodynamics, and exceptional powertrain integration. When configuring or maintaining a VNL, understanding its driveline specifications—specifically the transmission and axle gear ratios—is crucial for maximizing performance, whether your goal is pulling heavy grades or achieving maximum fuel efficiency on long-haul routes.

Below is a comprehensive guide to the transmission and axle gear ratios for the 2017 Volvo VNL.

Transmission gear ratios

The 2017 Volvo VNL was most commonly equipped with Volvo's proprietary 12-speed automated manual transmission, the I-Shift (such as the AT2612F). Traditional Eaton Fuller manual transmissions (like the 10-speed or 13-speed) were also available for fleets preferring a traditional standard shift.

Volvo I-Shift 12-Speed (Overdrive AT2612F)

Eaton Fuller 10-Speed Manual (FRO-16210C)

Available axle ratios

For the 2017 VNL, Volvo offered both proprietary and Meritor axles in single (4x2) or tandem (6x4) drive configurations. With the introduction of Volvo's XE (Exceptional Efficiency) downspeeding packages, numerically lower "fast" axle ratios became incredibly popular.

How to identify your axle ratio

Unlike passenger cars, Class 8 trucks like the Volvo VNL do not use standard RPO stickers in the glovebox. To determine your VNL's rear axle gear ratio, use the following methods:

1. Door Jamb VIN Plate: The primary build plate located on the driver-side door frame or B-pillar contains essential weight ratings and will often list the specific drive axle model and ratio (e.g., "Ratio: 2.64").
2. Axle Tag: Crawl beneath the rear of the truck and locate the metal tag bolted to the front or rear of the differential housing. For Meritor or Dana axles, this stamped tag will directly list the ratio alongside the model number.
3. VIN Decoder or Dealership: Because heavy-duty truck specs are highly customized, calling a Volvo Truck dealer with the last 6 digits of your VIN is the most foolproof way to retrieve the original factory build sheet, which includes the exact differential ratios.

Towing vs MPG impact

The relationship between your axle ratio and your truck's performance is governed by a simple rule:

• Numerically lower ratios (e.g., 2.47, 2.64): Often referred to as "fast" or "tall" gears, these are designed to lower engine RPM at highway speeds. This is the cornerstone of Volvo's "downspeeding" philosophy, where the engine cruises at highly efficient, low RPMs (around 1,050–1,150 RPM) at 65 mph. The result is significantly better fuel economy, though the truck may feel slightly sluggish when starting on an incline with a heavy load.
• Numerically higher ratios (e.g., 3.55, 3.90): Often referred to as "short" gears, these provide more mechanical torque multiplication to the wheels. This setup is better suited for heavy hauling, logging, or navigating mountainous terrain. The trade-off is higher cruising RPMs, which negatively impacts fuel economy on flat interstate stretches.

Common issues

While Volvo and Meritor axles are built for extreme durability, operating a high-mileage 2017 VNL requires keeping an eye out for a few known driveline issues:

• Power Divider/Inter-Axle Differential Wear: On 6x4 configurations, failing to lock or unlock the inter-axle differential correctly when experiencing wheel slip can cause severe damage to the power divider. A clunking noise when engaging the lock often signals damaged gears.
• Pinion Seal Leaks: Continuous heavy hauling can accelerate wear on the pinion seal, leading to gear oil leaks. If ignored, the fluid loss will eventually destroy the ring and pinion gears due to lack of lubrication.
• Carrier Bearing Wear: Vibrations felt in the cab under acceleration or deceleration can point to worn driveline carrier bearings or out-of-phase U-joints, which send shockwaves into the transmission and differentials.
• I-Shift Clutch Actuator: While the gears inside the I-Shift are robust, the pneumatic clutch actuator or transmission control module (TCM) air valves can occasionally stick or fail due to moisture in the air system.

Need to re-gear your rig, repair a leaking differential, or service your I-Shift? Find a driveline shop on Repairius.