2025 Ram 3500 Transmission & Axle Gear Ratios

Transmission gear ratios

The 2025 Ram 3500 offers robust powertrain options designed to handle the toughest tasks. Depending on your engine choice, you'll find different transmissions, each with specific gear ratios optimized for performance and efficiency.

6-speed automatic (68RFE)

This automatic transmission is paired with the 6.4L HEMI V8 engine, balancing power and smooth shifts for everyday driving and heavy-duty work.

Aisin 6-speed automatic (AS69RC)

Available with the 6.7L Cummins Turbo Diesel, this heavy-duty Aisin transmission is engineered for maximum towing and hauling capabilities.

Available axle ratios

The Ram 3500 provides a range of axle ratios to fine-tune your truck's performance based on your specific needs, whether it's maximizing towing capacity or optimizing fuel economy.

How to identify your axle ratio

Identifying your Ram 3500's axle ratio is crucial for understanding its performance characteristics. For Ram trucks, you can typically find this information on the door-jamb sticker, which often lists RPO (Regular Production Option) codes. Look for a three-digit code starting with "DM" followed by a number or letter combination (e.g., DM8 for 3.73, DMH for 4.10). Additionally, some Ram trucks may have an axle tag on the differential housing itself, displaying the ratio. For a definitive answer, a VIN decoder or a visit to a Ram dealership with your VIN can provide all the factory specifications.

Towing vs MPG impact

The choice of axle ratio significantly impacts both towing capability and fuel economy. A numerically higher axle ratio (e.g., 4.10) means the engine will turn more revolutions for every rotation of the wheels. This provides greater torque multiplication, which is excellent for heavy towing, accelerating with a load, and navigating steep grades. However, it also results in higher engine RPMs at cruising speeds, leading to decreased fuel efficiency.

Conversely, a numerically lower axle ratio (e.g., 3.73) allows the engine to operate at lower RPMs at cruising speeds. This reduces fuel consumption and is generally preferred for highway driving and lighter loads. While it offers better MPG, it reduces the overall mechanical advantage, meaning less power available for significant towing tasks. Choosing the right balance depends entirely on your primary use case for the Ram 3500.

Common issues

While Ram axles are known for their durability, like any heavy-duty component, they can experience wear over time. Common issues to be aware of include:

• Ring and Pinion Whine: A persistent howling or whining noise that changes with vehicle speed, often indicating wear or improper mesh between the ring and pinion gears. This can be caused by improper installation, lack of lubrication, or excessive load.
• Carrier Bearing Wear: The carrier bearings support the differential carrier within the axle housing. Worn carrier bearings can produce a rumbling or clunking noise, especially during turns or when accelerating. This can lead to excessive play in the differential, potentially damaging other components.
• Limited-Slip Clutch Wear (if equipped): If your Ram 3500 is equipped with a limited-slip differential, the clutches within it can wear out over time, especially with hard use. Symptoms include a chattering or grinding noise from the rear end during turns, and a diminished ability to transfer power effectively to both wheels.

Regular maintenance, including proper differential fluid changes, can help mitigate these issues and extend the life of your axle components.

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