2016 Ram 3500: Transmission & Axle Gear Ratios

Transmission Gear Ratios

The 2016 Ram 3500 was available with three different transmissions, each engineered to handle the immense torque from its available Cummins diesel and Hemi gasoline engines. The G56, a heavy-duty six-speed manual, was a rare but sought-after option for traditionalists. The 68RFE was the standard automatic for the 5.7L and 6.4L Hemi V8s, while the commercial-grade Aisin AS69RC was paired with the high-output Cummins diesel.

Chrysler 68RFE — 6-Speed Automatic

Aisin AS69RC — 6-Speed Automatic

Mercedes-Benz G56 — 6-Speed Manual

Available Axle Ratios

The rear axle ratio is the final critical link in the powertrain, multiplying torque one last time before it hits the pavement. Selecting the right ratio is a balancing act between raw towing power and long-haul fuel efficiency. Ram offered a wide range of options to suit any need, from fuel-conscious highway cruising to maximum-effort gooseneck towing.

How to Identify Your Axle Ratio

Not sure which ratio your truck is equipped with? There are a few easy ways to find out.

• Axle Tag (Most Reliable for Ram/Ford): Look for a small metal tag bolted to the differential cover on the rear axle. This tag will have several numbers stamped on it. You are looking for a set of numbers that looks like "3 73" (for a 3.73 ratio) or "4 10" (for a 4.10). Sometimes it will be presented as a decimal (3.73) or without a space. If the numbers have worn off, you can try cleaning the tag with a wire brush.
• VIN Decoder: Numerous online VIN decoders can provide a build sheet or a list of your truck's factory-installed options, which will include the axle ratio.
• Glove Box Sticker: Unlike GM, which places an RPO code sticker in the door jamb, Ram trucks often have a "Sales Code" sticker inside the glove compartment. Look for one of the codes listed in the table above (e.g., DMM, DMH, DRE) to identify your ratio.

Towing vs. MPG Impact

The relationship between axle ratios, towing, and fuel economy is a matter of mechanical advantage.

• Numerically Higher Ratios (e.g., 4.10, 4.30): These are often called "shorter" gears. The engine has to turn more times for each rotation of the wheels. This provides a significant torque multiplication advantage, making it easier to get a heavy load moving from a standstill and maintain speed on a grade. The trade-off is higher engine RPM at cruising speed, which leads to lower fuel economy.

• Numerically Lower Ratios (e.g., 3.42, 3.73): These are called "taller" gears. The engine turns fewer times for every wheel rotation. This is ideal for highway cruising, as it keeps the engine RPM low, reducing fuel consumption and engine noise. However, it provides less mechanical advantage for towing, meaning the engine and transmission have to work harder to pull heavy loads.

For the 2016 Ram 3500, a 3.42 ratio is excellent for an owner who does minimal towing and prioritizes MPG. The 3.73 is a fantastic all-around gear, offering a great compromise. The 4.10 and 4.30 ratios are the undisputed champions for those who frequently tow at or near the truck's maximum rated capacity.

Common Issues

While the AAM (American Axle & Manufacturing) axles used in the 2016 Ram 3500 are robust, they are not immune to problems, especially under heavy use.

• Pinion Bearing Whine: A high-pitched whining noise that changes with vehicle speed (not engine RPM) is a classic symptom of a failing pinion bearing. This is often caused by high mileage, heavy loads, or contaminated gear oil.
• Carrier Bearing Failure: A rumbling or growling noise, particularly noticeable on turns, can indicate a worn carrier bearing. This requires disassembling the differential to replace.
• Limited-Slip Clutch Wear (if equipped): Trucks with the optional limited-slip differential (LSD) can experience clutch pack wear over time. This may present as a chattering or groaning sound from the rear end during tight turns. Using the correct gear oil with a friction modifier additive is critical for LSD longevity.

If you hear any unusual noises from your truck's driveline, it's best to have it inspected by a qualified technician before a minor issue becomes a major failure.

Find a driveline shop on Repairius.