2016 Ram 1500 — Transmission & Axle Gear Ratios

Transmission gear ratios

The 2016 Ram 1500 was offered with two automatic transmission options:

8-Speed 845RE Automatic (TorqueFlite 8)

6-Speed 65RFE Automatic

Available axle ratios

The 2016 Ram 1500 offered a variety of axle ratios to cater to different needs, from fuel economy to heavy towing. These ratios often varied depending on the engine, trim level, and specific packages.

Note: While the RPO code is often the same (DMH for most axles), the final ratio is different. This is a common point of confusion.

How to identify your axle ratio

Unlike GM vehicles with RPO stickers listing specific axle codes, Ram trucks typically require a different approach.

Axle Tag: The most reliable way to identify your Ram's axle ratio is to locate a metal tag attached to one of the differential cover bolts on the rear axle. This tag will usually have the gear ratio stamped on it (e.g., 3.21, 3.55, 3.92). It may also include other information like the differential type.

VIN Decoder: You can use your vehicle's VIN to get a build sheet from a Ram dealer or an online VIN decoder service. This build sheet will list all the original equipment, including the axle ratio, as delivered from the factory.

Door Jamb Sticker (Limited Information): While not providing the specific ratio, the door jamb sticker on a Ram 1500 will list the Gross Vehicle Weight Rating (GVWR) and Gross Axle Weight Rating (GAWR). This information, along with your engine and transmission, can sometimes help narrow down the possibilities, but it is not a definitive source for the exact ratio.

Towing vs MPG impact

The axle ratio plays a crucial role in determining the balance between towing capability and fuel economy.

• Numerically Lower Ratio (e.g., 3.21, 3.55): A numerically lower axle ratio means the engine spins fewer times per rotation of the wheels at a given road speed. This results in lower engine RPMs at cruising speeds, leading to better fuel economy. However, it also means less mechanical advantage for accelerating or towing heavy loads. Trucks with lower ratios will feel less responsive when pulling a trailer.

• Numerically Higher Ratio (e.g., 3.92): Conversely, a numerically higher axle ratio means the engine spins more times per wheel rotation. This provides greater mechanical advantage, making the truck feel more powerful off the line and significantly improving its towing capacity. The trade-off is higher engine RPMs at cruising speeds, which translates to reduced fuel economy.

For the 2016 Ram 1500, a 3.21 ratio is ideal for owners prioritizing fuel efficiency and who rarely tow heavy loads. The 3.55 offers a good compromise for mixed driving and occasional towing. If you plan on frequently towing heavy trailers or engaging in serious off-road activities, the 3.92 ratio is the preferred choice for its enhanced capability.

Common issues

While generally robust, differential and axle components can experience wear over time.

• Ring & Pinion Whine: A persistent high-pitched whine that changes with vehicle speed (but not engine RPM in independent gears) can indicate wear on the ring and pinion gears. This often becomes more noticeable during deceleration or at specific speeds. Ignoring this can lead to further damage.

• Carrier Bearing Wear: The carrier bearings support the differential carrier within the axle housing. Worn bearings can manifest as a growling or humming noise, especially when turning or accelerating. If left unaddressed, this can lead to excessive play and eventual differential failure.

• Limited-Slip Clutch Wear (if equipped): Many Ram 1500s were available with a limited-slip differential. Over time, the clutches within these units can wear out, leading to a loss of traction in low-traction situations. Symptoms may include a popping or clunking noise from the rear axle during slow turns, or uneven tire wear. Regular differential fluid changes with the correct friction modifier are essential for limited-slip units.

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