2020 Ram 1500 Transmission & Axle Gear Ratios

Transmission gear ratios

The 2020 Ram 1500 exclusively utilized the robust ZF 8HP75 eight-speed automatic transmission, often branded by Ram as the "TorqueFlite 8." This sophisticated transmission provides a wide range of ratios to balance acceleration, towing capability, and fuel efficiency.

Available axle ratios

The 2020 Ram 1500 offered a selection of axle ratios to cater to different needs, from maximizing fuel economy to heavy-duty towing.

How to identify your axle ratio

Identifying the axle ratio on your 2020 Ram 1500 is crucial for proper maintenance, part replacement, and understanding your truck's capabilities. The easiest way for Ram owners is typically to check the glove box or the door jamb sticker for the build sheet or RPO (Regular Production Option) codes. Look for a three-digit code starting with "DM" followed by a letter, such as "DMH". Sometimes the specific ratio is directly listed. If that's not available, a VIN decoder can often provide the full build sheet, including the axle ratio. For a definitive answer, you may need to visually inspect the axle housing for a tag, although these can become unreadable over time. Another method is to jack up the rear of the truck, mark the driveshaft and tire, and rotate the tire a full revolution while counting the driveshaft rotations. This manual method provides a close approximation of your ratio.

Towing vs MPG impact

The axle ratio plays a significant role in determining a vehicle's performance characteristics, specifically in the trade-off between towing capability and fuel economy. A numerically lower axle ratio (e.g., 3.21) means the engine will run at lower RPMs at a given road speed. This generally translates to better fuel economy on the highway because the engine doesn't have to work as hard to maintain speed. However, with a lower ratio, the engine has less leverage to get the vehicle moving or to pull heavy loads, resulting in reduced towing capacity and slower acceleration.

Conversely, a numerically higher axle ratio (e.g., 3.92) means the engine will operate at higher RPMs at the same road speed. This provides greater torque multiplication, which significantly improves towing capacity and off-the-line acceleration. The downside is that the engine will consume more fuel, especially at highway speeds, due to the higher RPMs. For the 2020 Ram 1500, the 3.21 ratio is ideal for owners prioritizing fuel efficiency for daily driving and light hauling, while the 3.92 ratio is the preferred choice for those who frequently tow heavy trailers or engage in off-road activities where maximum torque is beneficial. The 3.55 ratio offers a balanced compromise for varied use.

Common issues

While the 2020 Ram 1500's driveline components are generally robust, like any mechanical system, they can experience wear and issues over time. Common issues associated with axle assemblies include:

• Ring and Pinion Whine: This often manifests as a high-pitched hum or whine that changes with vehicle speed and throttle input. It can be caused by improper gear setup, wear, or damage to the ring and pinion gears.
• Carrier Bearing Wear: The carrier bearings support the differential carrier within the axle housing. Wear can lead to a rumbling or grinding noise, especially when cornering or accelerating.
• Limited-Slip Clutch Wear: For vehicles equipped with a limited-slip differential, the clutch packs can wear out over time, leading to a loss of traction in low-traction situations and sometimes a chattering or clunking sound when turning tightly.

Regular differential fluid changes using the manufacturer-specified fluid are crucial for prolonging the life of these components and preventing premature wear.

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