2018 Mercedes-Benz Metris Transmission & Axle Gear Ratios

Transmission gear ratios

The 2018 Mercedes-Benz Metris comes standard with a single transmission option, the 7G-TRONIC PLUS (722.9) seven-speed automatic transmission.

Available axle ratios

The 2018 Mercedes-Benz Metris offered a few axle ratio options to complement its powertrain, allowing for some customization based on the intended use of the vehicle. These ratios were often tied to specific packages or were available as standalone options.

How to identify your axle ratio

Identifying the axle ratio on your 2018 Mercedes-Benz Metris is crucial for maintenance, repairs, or performance modifications. Unlike some domestic manufacturers, Mercedes-Benz vehicles typically do not use a readily identifiable RPO sticker on the door jamb for axle codes. Instead, you'll usually find the axle code listed on a data plate or sticker within the vehicle, often in the engine bay or on the driver's side door-jamb, detailing various vehicle specifications. For the most accurate information, you can also check the vehicle's build sheet or consult a Mercedes-Benz dealership with your VIN. The axle code will usually appear as a three-digit number or a designation like "I=3.271," "I=3.472," or "I=3.727," which directly corresponds to the final drive ratio.

Towing vs MPG impact

The choice of axle ratio significantly impacts both the towing capability and fuel economy of your 2018 Mercedes-Benz Metris. A numerically lower axle ratio (e.g., 3.27) means that for every revolution of the driveshaft, the wheels turn fewer times. This results in lower engine RPMs at cruising speeds, leading to better fuel economy. However, it also means less mechanical advantage for towing or hauling heavy loads, making the engine work harder.

Conversely, a numerically higher axle ratio (e.g., 3.73) means the wheels turn more times for every revolution of the driveshaft. This provides greater torque multiplication, which is beneficial for towing heavy trailers or operating in demanding conditions. The trade-off is higher engine RPMs at cruising speeds, which generally leads to decreased fuel economy. The balanced 3.47 ratio offers a good compromise, providing decent towing capabilities without severely impacting fuel efficiency.

Common issues

While the Mercedes-Benz Metris is generally reliable, like any vehicle, its driveline components can experience wear over time. Common issues related to the axle and differential can include:

• Ring & Pinion Whine: A persistent high-pitched whine that changes with vehicle speed, especially during acceleration or deceleration, can indicate wear or improper setup of the ring and pinion gears within the differential. This often requires disassembly and replacement of the gears.
• Carrier Bearing Wear: The bearings that support the differential carrier can wear out, leading to a humming or growling noise that typically changes with vehicle speed. This can also cause vibrations. Neglecting this issue can lead to more significant damage to the differential.
• Limited-Slip Clutch Wear (if equipped): Some differentials may be equipped with a limited-slip mechanism. Over time, the clutch packs within these units can wear, leading to a chattering or clunking noise, especially during turns. This can also reduce the effectiveness of the limited-slip feature. Regular fluid changes with the correct friction modifiers are crucial for these differentials.

Regular maintenance, including differential fluid changes at recommended intervals, can help mitigate these issues and prolong the life of your Metris's driveline components.

Find a driveline shop on Repairius.