2020 Jeep Cherokee Transmission & Axle Gear Ratios

Transmission gear ratios

The 2020 Jeep Cherokee offers two primary transmission options: the 9-speed automatic and a CVT (for certain export models, though less common in North America). The 9-speed automatic is the more prevalent choice for the US market.

ZF 9HP48 9-Speed Automatic (948TE)

This transmission is paired with most engine options in the 2020 Cherokee, offering a wide gear spread for both fuel efficiency and strong acceleration.

Available axle ratios

The 2020 Jeep Cherokee features several axle ratio options, depending on the engine, trim level, and specific powertrain configuration. These ratios play a significant role in determining the vehicle's overall performance characteristics, including towing capability and fuel economy.

Note: Front and rear axle ratio codes can sometimes differ slightly due to variations in RPO codes for front and rear differentials, even if the effective ratio is the same. Always verify with your specific vehicle's RPO sticker.

How to identify your axle ratio

For most Stellantis (formerly FCA) vehicles, including the 2020 Jeep Cherokee, you can often find information about your vehicle's axle ratio on the RPO (Regular Production Option) sticker. This sticker is typically located on the driver's side door jamb. Look for three-digit codes that start with "DM" such as DMZ, DME, DMH, DMM, DML. You may need to cross-reference these codes with a Jeep RPO decoder or consult a dealership to confirm the exact ratio. The owner's manual or a VIN decoder tool can also be helpful resources.

Some vehicles may also have a metal tag attached to one of the axle housing bolts, though this is less common on modern unibody SUVs like the Cherokee compared to traditional truck-based platforms. If present, this tag will typically stamp the axle ratio directly.

Towing vs MPG impact

The choice of axle ratio has a direct and significant impact on a vehicle's performance, particularly regarding towing capability and fuel economy:

• Numerically lower ratio (e.g., 3.25): A numerically lower axle ratio means the engine will operate at lower RPMs at a given road speed. This generally results in better fuel economy on the highway. However, it also means the engine will have to work harder to get the vehicle moving and maintain speed under load, which can reduce towing capacity and make the vehicle feel less responsive.

• Numerically higher ratio (e.g., 3.73): Conversely, a numerically higher axle ratio causes the engine to rev higher at the same road speed. This provides greater torque multiplication, leading to improved towing capability, better off-road performance, and snappier acceleration. The trade-off is typically reduced fuel economy due to the engine operating at higher RPMs.

For the 2020 Jeep Cherokee, if you plan on frequent heavy towing or serious off-roading (especially with the Trailhawk trim), a higher axle ratio like the 3.73 or 3.517 will be more beneficial. For mostly highway driving and lighter loads, the 3.25 ratio would offer better fuel efficiency.

Common issues

While the 2020 Jeep Cherokee generally has a robust driveline, when discussing axle ratios and differentials, a few common issues can arise in any vehicle:

• Ring & Pinion Whine: This often manifests as a specific humming or whining noise that changes pitch with vehicle speed, often most noticeable during deceleration or under light load. It can indicate improper gear setup (backlash), worn gear teeth, or worn pinion bearings. This is less common in newer vehicles unless there has been an impact or incorrect service.

• Carrier Bearing Wear: The carrier bearings support the differential carrier within the axle housing. Wear here can lead to excessive play, noise, and eventually failure if not addressed. A rumbling noise that changes with speed can sometimes indicate carrier bearing issues.

• Limited-Slip Clutch Wear (if equipped): Some Cherokees, particularly those equipped for off-road or towing, might have a limited-slip differential. The clutch packs in these differentials can wear out over time, leading to a loss of the limited-slip function and potentially chattering or groaning noises, especially when turning at low speeds.

Regular differential fluid changes, especially for vehicles used for towing or off-roading, can help mitigate some of these issues and extend the life of the components.

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