2019 Ram 3500: Transmission & Axle Gear Ratios

Transmission Gear Ratios

The 2019 Ram 3500 was available with two main automatic transmissions, each paired with specific engines.

68RFE 6-Speed Automatic (6.4L HEMI V8)

This transmission is the standard offering for the gas-powered 6.4L HEMI V8 engine.

Aisin AS69RC 6-Speed Automatic (6.7L Cummins Turbo Diesel)

Considered a more robust, commercial-grade unit, the Aisin AS69RC is paired exclusively with the 6.7L Cummins Turbo Diesel engine, including the high-output version.

Available Axle Ratios

The axle ratio is the final piece of the gearing puzzle, multiplying the torque delivered to the wheels. Ram offered several ratios for the 2019 3500, tailored for different applications from fuel efficiency to maximum towing.

How to Identify Your Axle Ratio

Knowing your truck's specific axle ratio is crucial for ordering parts or understanding its towing capabilities. Here are the primary ways to identify it:

1. Glove Box Sticker: Unlike GM, which uses a door-jamb sticker, Ram places the vehicle information sticker, including axle specifications, inside the glove compartment. Look for terms like "Anti-Spin Differential Rear Axle" followed by the ratio (e.g., 3.73 or 4.10).

2. Axle Tag: Look for a small metal tag bolted to the differential cover (the pumpkin-shaped housing in the middle of the rear axle). This tag will have information stamped into it, often including the ratio (e.g., "3 73" for 3.73 or "4 10" for 4.10).

3. VIN Decoder: Numerous online VIN decoder services can provide a full build sheet for your truck. When you input your 17-digit VIN, the report should list the axle ratio it was built with from the factory.

Towing vs. MPG Impact

The trade-off between power and efficiency is directly tied to the axle gear ratio. The concept is straightforward:

• Numerically Higher Ratio (e.g., 4.10): This is known as a "shorter" gear. The engine needs to turn more times for every single rotation of the wheels. This provides more torque multiplication, making it easier to get a heavy load moving from a standstill. This is ideal for towing heavy trailers but results in higher engine RPM at highway speeds, leading to lower fuel economy.

• Numerically Lower Ratio (e.g., 3.73): This is a "taller" gear. The engine turns fewer times for every wheel rotation. This is less effective for getting extreme loads moving but allows the engine to operate at a lower, more efficient RPM on the highway. This is best for maximizing fuel economy when not towing, or for towing lighter loads.

For the 2019 Ram 3500, the 4.10 axle ratio is a key component in achieving the maximum advertised towing capacity, especially when paired with the High Output Cummins engine.

Common Issues

The axles used in the Ram 3500 are generally robust, but like any heavy-duty component, they can experience wear over time, especially under heavy use.

• Pinion Bearing Whine: A high-pitched whining sound that changes with vehicle speed (not engine RPM) can indicate a worn pinion bearing. This is often one of the first signs of internal differential wear.
• Carrier Bearing Noise: A rumbling or roaring noise, also dependent on vehicle speed, can point to worn carrier bearings. This is often more noticeable on turns.
• Limited-Slip Clutch Wear: If your truck is equipped with an anti-spin (limited-slip) differential, the internal clutches can wear out over time. This may present as a chattering or groaning sound during slow, tight turns.

Addressing these driveline noises early is key to preventing more catastrophic and expensive failures. Regular differential fluid changes are the best preventative maintenance.

Need to diagnose a noise or service your differential? Find a trusted, independent driveline shop in your area on Repairius.com.