2018 Nissan Armada Transmission Problems

The 2018 Nissan Armada, a full-size SUV known for its robust capabilities and comfortable ride, relies on a sophisticated automatic transmission to deliver power from its V8 engine to the wheels. While generally reliable, certain issues have surfaced in some 2018 Armada models, prompting curiosity and concern among owners and enthusiasts alike. This article delves into the common transmission problems reported for the 2018 Nissan Armada, dissecting the potential causes and offering a technically informed perspective.

The RE7R01H Transmission: An Overview

Before diving into specific problems, it's crucial to understand the transmission at the heart of the matter: the RE7R01H. This is a 7-speed automatic transmission manufactured by JATCO (Japanese Automatic Transmission Company), a common supplier for Nissan and other automakers. The "RE" designates a rear-wheel-drive electronic transmission. The "7" signifies the number of forward gears, and the "R01H" is a specific model designation.

Key features of the RE7R01H include:

Wide gear ratio spread: Seven gears allow for a wide range of gear ratios, contributing to both fuel efficiency and strong acceleration.
Adaptive Shift Control (ASC): This system monitors driving conditions and adjusts shift points to optimize performance and fuel economy.
Downshift Rev Matching (DRM): This feature blips the throttle during downshifts, smoothing gear transitions and preventing jolts.
Electronic controls: The transmission is controlled electronically, allowing for precise and responsive shifting.

Understanding these basic features provides context for understanding the potential failure points.

Common Transmission Problems in the 2018 Armada

While the RE7R01H is generally considered a robust transmission, some 2018 Armada owners have reported specific issues. These problems often manifest as:

1. Harsh Shifting

One of the most frequently reported complaints is harsh or jerky shifting, particularly between certain gears. This can manifest as a noticeable jolt during acceleration or deceleration. The potential causes are multifaceted:

Low Transmission Fluid: Insufficient fluid can lead to poor lubrication and increased friction within the transmission, resulting in harsh shifts. Checking the fluid level is a critical first step in diagnosing this issue.
Degraded Transmission Fluid: Over time, transmission fluid degrades, losing its lubricating properties and becoming contaminated with wear particles. This can cause similar symptoms to low fluid. A transmission fluid flush and replacement might be necessary.
Faulty Solenoid Valves: Solenoids are electromechanical valves that control the flow of transmission fluid to different clutches and bands. If a solenoid is failing, it may not properly control fluid pressure, leading to erratic shifting. Diagnostic trouble codes (DTCs) related to specific solenoids can help pinpoint the problem.
Valve Body Issues: The valve body is the hydraulic control center of the transmission. Wear and tear or contamination can cause valves within the valve body to stick or malfunction, leading to harsh shifts.
Software Glitches: In some cases, software glitches in the Transmission Control Module (TCM) can cause incorrect shift patterns or harsh shifting. A TCM reflash by a qualified technician can sometimes resolve this issue.
Mechanical Wear: While less common in relatively newer vehicles, significant internal wear to clutches or bands can also cause harsh shifting. This usually involves more extensive repairs.

2. Slipping Gears

Gear slippage occurs when the engine revs up without a corresponding increase in vehicle speed. This can be a dangerous issue, especially at higher speeds. Possible causes include:

Low Transmission Fluid: Similar to harsh shifting, low fluid can cause clutches to slip due to insufficient hydraulic pressure.
Worn Clutches: The clutches within the transmission are responsible for engaging different gears. Over time, these clutches can wear down, reducing their ability to grip and transmit power.
Internal Leaks: Internal leaks within the transmission can reduce hydraulic pressure, leading to clutch slippage.
Torque Converter Issues: The torque converter is responsible for multiplying engine torque before it reaches the transmission. A failing torque converter can cause slippage, especially during acceleration.

3. Delayed Engagement

Delayed engagement refers to a noticeable pause between shifting into drive or reverse and the vehicle actually moving. This often points to hydraulic problems within the transmission:

Low Transmission Fluid: Again, low fluid is a prime suspect.
Pump Problems: The transmission pump is responsible for generating hydraulic pressure. A failing pump may not be able to build pressure quickly enough, leading to delayed engagement.
Valve Body Issues: As with harsh shifting, problems within the valve body can disrupt hydraulic flow and cause delayed engagement.
Filter Clogging: A clogged transmission filter can restrict fluid flow and reduce hydraulic pressure.

4. Transmission Overheating

While less common, transmission overheating can occur, especially under heavy load conditions like towing or driving in hot weather. Overheating can damage internal components and lead to premature failure. Contributing factors include:

Heavy Towing Without Proper Cooling: The 2018 Armada is capable of towing, but exceeding the vehicle's towing capacity or towing without proper cooling equipment (e.g., a transmission cooler) can lead to overheating.
Low Transmission Fluid: Insufficient fluid can reduce the transmission's ability to dissipate heat.
Clogged Transmission Cooler: The transmission cooler is responsible for removing heat from the transmission fluid. A clogged cooler can reduce its efficiency.
Stuck Thermostat: A malfunctioning thermostat can prevent the transmission cooler from operating effectively.
Internal Friction: Excessive internal friction due to worn components can generate excessive heat.

Diagnosis and Repair

Diagnosing transmission problems requires a systematic approach. The following steps are generally involved:

Visual Inspection: Check for leaks and the overall condition of the transmission.
Fluid Level and Condition Check: Verify the fluid level and examine its color and smell. Burnt or dark fluid indicates a problem.
Diagnostic Trouble Code (DTC) Scan: Use a scan tool to retrieve any stored DTCs. These codes can provide valuable clues about the nature of the problem. Codes related to solenoids, sensors, or specific gear ratios are particularly informative.
Live Data Analysis: Monitor live data from the transmission sensors using a scan tool. This can help identify erratic sensor readings or other anomalies.
Pressure Testing: Check the transmission's hydraulic pressure at various test ports. Low pressure can indicate a pump problem or internal leak.
Stall Test: A stall test can help assess the torque converter's performance.
Road Test: Evaluate the transmission's performance under various driving conditions.

Repair options range from simple fixes like fluid replacement to more complex procedures like valve body repair or complete transmission replacement. It's crucial to consult a qualified and experienced transmission technician for accurate diagnosis and repair. Replacing the transmission fluid with Nissan Matic S fluid is critical. Using aftermarket fluids can often result in improper transmission performance and possible damage.

Preventive Maintenance

Preventive maintenance is key to extending the life of the transmission and avoiding costly repairs. Recommendations include:

Regular Fluid Changes: Follow Nissan's recommended maintenance schedule for transmission fluid changes. Shorter intervals are recommended for vehicles used for heavy towing or in severe driving conditions.
Transmission Cooler Installation: If you frequently tow with your Armada, consider installing an aftermarket transmission cooler.
Avoid Overloading: Do not exceed the vehicle's recommended towing capacity.
Monitor Transmission Temperature: If possible, monitor the transmission temperature, especially when towing.
Address Problems Promptly: Don't ignore warning signs like harsh shifting or slippage. Addressing problems early can prevent them from escalating into more serious issues.

In conclusion, while the 2018 Nissan Armada's RE7R01H transmission is generally reliable, certain issues can arise. Understanding the potential problems, their causes, and the proper diagnostic procedures can empower owners to take proactive steps and ensure the longevity of their vehicle's transmission. Regular maintenance and prompt attention to any warning signs are crucial for maintaining the smooth and reliable operation of this vital component.