2018 Mercedes-Benz Metris Transmission Fluid & Service Guide

Quick Answer

• Transmission Make/Model: Mercedes-Benz 722.9 7G-TRONIC PLUS (NAG2FEV+)
• OEM Fluid Spec: Mercedes-Benz ATF MB 236.15 (blue in color)
• Drain & Fill Capacity: Approximately 5.0 - 6.5 liters (depending on procedure and how much drains)
• Full Overhaul Capacity: Approximately 9.7 liters
• Filter OEM Part Number: Verify with dealer or service manual (typically A 222 277 20 00 or similar for 722.9 transmissions)
• Recommended Service Interval: Every 75,000 miles or 5 years, whichever comes first (for normal driving conditions). Severe duty applications may require more frequent changes.

Fluid Type Explained

The 2018 Mercedes-Benz Metris, when equipped with the 7G-TRONIC PLUS (NAG2FEV+) transmission (model 722.9), requires a very specific automatic transmission fluid (ATF). The OEM specification is Mercedes-Benz ATF MB 236.15. This fluid is distinctive for its blue color. It's crucial to use only fluids that meet or exceed this spec. Using an incorrect fluid, such as the older MB 236.14 specification (which is red), can lead to noticeable shift quality issues, premature wear, and potential transmission damage. The 7G-TRONIC PLUS transmission is designed for optimal performance with the lower viscosity and specialized additives found in the 236.15 fluid, which contributes to improved fuel economy and smoother shifts.

Service Procedure

Servicing the 7G-TRONIC PLUS transmission in your Metris can be done via a drain and fill method or a full fluid exchange. A complete fluid exchange is generally recommended for optimal longevity, but a drain and fill is also acceptable if performed regularly.

Drain & Fill

The drain and fill procedure involves simply draining the fluid from the transmission pan and refilling it with fresh fluid. This method typically replaces about 50-70% of the total transmission fluid. This process does not remove all the old fluid from the torque converter and other internal components. To perform a proper drain and fill, the vehicle should be on a level surface, and the fluid temperature should be within a specific range for accurate level setting. Special tools, such as a fill adapter, are usually required because Mercedes-Benz transmissions are often filled through the pan with a standpipe to set the correct level. The approximate capacity for a drain and fill is 5.0 to 6.5 liters.

Full Fluid Exchange

A full fluid exchange (or "flush") involves using specialized equipment to circulate new fluid throughout the entire transmission system, including the torque converter and cooler lines, effectively pushing out nearly all of the old fluid. This method provides the most thorough cleaning and replacement of transmission fluid. Given the complexity and sealed-for-life (though serviceable) nature of these transmissions, a full exchange is often preferred for maintaining peak performance and extending the life of the unit. The full overhaul capacity is approximately 9.7 liters.

Regardless of the method chosen, replacing the transmission filter and pan gasket is highly recommended. The filter helps trap contaminants that can damage internal components. Always use genuine Mercedes-Benz parts or high-quality aftermarket equivalents that meet OEM specifications for gaskets and filters. Verify the correct filter OEM part number (typically A 222 277 20 00 or similar for 722.9 transmissions) with your dealer or service manual.

Service Interval

Mercedes-Benz initially marketed some of their automatic transmissions as "sealed for life," implying no service was needed. However, general consensus among technicians and updated service recommendations specify regular maintenance is vital. For the 7G-TRONIC PLUS transmission in your 2018 Metris, the recommended service interval is every 75,000 miles or 5 years, whichever comes first, under normal driving conditions.

Severe Duty / Towing: If your Metris is used for heavy-duty applications such as frequent towing, consistent heavy loads, or extensive stop-and-go city driving in hot climates, it is wise to shorten the service interval significantly. Consider servicing the transmission every 30,000 to 50,000 miles or every 2-3 years. Elevated temperatures and increased stress on the transmission can accelerate fluid degradation, making more frequent changes a cost-effective preventative measure.

Common Transmission Problems

The Mercedes-Benz 722.9 7G-TRONIC PLUS transmission is generally considered robust, but like any complex mechanical system, it can develop issues. For this generation, some common problems or areas of concern include:

• Conductor Plate Issues: The conductor plate (also known as the valve body or mechatronic unit) houses the solenoids and speed sensors. Over time, these can fail, leading to symptoms like harsh shifting, delayed engagement, or the transmission going into "limp home" mode. While less prevalent in later iterations of the 722.9, it's still a known weak spot in the family.
• Torque Converter Shudder: Some owners may experience a shudder or vibration, particularly under light acceleration or during certain gear changes. This can sometimes be attributed to torque converter issues, though fluid condition also plays a significant role. Correct fluid type and regular changes can often mitigate this.
• Fluid Leaks: As with any transmission, seals and gaskets can degrade over time, leading to fluid leaks. Pay attention to any red or blue fluid stains under your vehicle. Early detection and repair can prevent more significant problems.
• Software Issues: Mercedes-Benz vehicles are highly computerized. Transmission performance can sometimes be affected by software glitches or outdated programming. Regular diagnostic checks and software updates at an authorized Mercedes-Benz service center can resolve these.
• Delayed or Harsh Shifting: This can be a symptom of various issues, including low fluid levels, incorrect fluid type, worn solenoids, or internal wear. Proper diagnosis is key to identifying the root cause.

Regular transmission fluid and filter changes with the correct specification fluid are the best defense against these common problems, ensuring your Metris continues to shift smoothly and reliably.

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