2023 Ram 3500 Transmission & Axle Gear Ratios

Transmission gear ratios

The 2023 Ram 3500 offers two robust transmission options to handle its impressive capabilities: the 8HP75 8-speed automatic for gasoline engines and the Aisin AS69RC 6-speed automatic for Cummins diesel engines.

ZF 8HP75 8-Speed Automatic (Gasoline Hemi)

Aisin AS69RC 6-Speed Automatic (Cummins Diesel)

Available axle ratios

The 2023 Ram 3500 offers a range of axle ratios to optimize for various tasks, from everyday driving to heavy-duty towing. The availability often depends on the engine, trim level, and specific packages.

Note: Specific availability can vary based on configuration and package. Always verify with your dealer or vehicle documentation.

How to identify your axle ratio

For Ram trucks, identifying your axle ratio is typically straightforward:

• Door-Jamb RPO Sticker: Check the sticker on the driver's side door jamb (or sometimes inside the glove compartment). Look for a three-digit alphanumeric code. Common axle codes include "DPC" for 3.73 and "DPL" or "DPM" for 4.10. These codes correspond to the "Rear Axle Ratio" option.
• Axle Tag: Some Ram trucks may have a metal tag bolted to one of the differential cover bolts. This tag will often clearly list the gear ratio (e.g., "3.73" or "4.10").
• VIN Decoder: You can use an online VIN decoder service or contact a Ram dealership with your VIN. They can provide a detailed build sheet for your specific truck, which will include the axle ratio.

Towing vs MPG impact

The choice of axle ratio significantly impacts both towing performance and fuel economy:

• Numerically Lower Ratio (e.g., 3.73): A numerically lower ratio means the engine turns fewer times for each rotation of the wheels. This generally results in better fuel economy at highway speeds because the engine operates at lower RPMs. However, it also means less mechanical advantage for towing. While still capable, a 3.73 ratio might require the engine to work harder and downshift more frequently when towing very heavy loads, potentially reducing efficiency and increasing wear.

• Numerically Higher Ratio (e.g., 4.10): A numerically higher ratio means the engine turns more times for each rotation of the wheels. This provides a greater mechanical advantage, making it easier to launch and pull heavy loads. It significantly improves towing capability, especially with maxed-out trailers or in hilly terrain. The trade-off is often reduced fuel economy, particularly at higher speeds, as the engine will be revving at higher RPMs.

For the 2023 Ram 3500, a 3.73 ratio is a good balance for general-purpose use and occasional heavy towing. If you frequently tow near the truck's maximum capacity or need superior low-end grunt, the 4.10 ratio is the better choice.

Common issues

While the drivetrains of the Ram 3500 are built for durability, certain issues can arise over time, particularly with heavy use or inadequate maintenance:

• Ring and Pinion Whine: A high-pitched whine that changes with vehicle speed (and sometimes load) can indicate wear or improper setup of the ring and pinion gears within the differential. This is often more noticeable during deceleration or at specific speed ranges.
• Carrier Bearing Wear: The carrier bearings support the differential carrier. If these bearings start to wear, they can produce a growling or humming noise, especially when turning or accelerating. Ignoring this can lead to further damage to the differential.
• Limited-Slip Clutch Wear (if equipped): Trucks equipped with a limited-slip differential rely on clutches to transfer power to the wheel with the most traction. Over time, these clutches can wear out, leading to chatter or clunking noises during turns, or a reduction in the limited-slip differential's effectiveness.
• Fluid Leaks: Inspect for leaks around the differential cover, pinion seal, and axle seals. Leaks can indicate failing seals or gaskets and can lead to low fluid levels, which can cause accelerated wear and damage.

Regular maintenance, including differential fluid changes at recommended intervals, is crucial for preventing these issues and ensuring the longevity of your Ram 3500's drivetrain.

Find a driveline shop on Repairius.