2009 Nissan Altima Cvt Transmission

The 2009 Nissan Altima marked a pivotal point in the adoption of Continuously Variable Transmissions (CVTs) in mainstream vehicles. While CVTs had existed before, the Altima's implementation helped popularize, and ultimately scrutinized, the technology in the eyes of everyday drivers. This article will delve deep into the workings of the 2009 Altima's CVT, exploring its design, operation, advantages, disadvantages, and common issues.

The JATCO JF011E: A CVT Under the Hood

The heart of the 2009 Altima's CVT is the JATCO JF011E transmission, also known as the RE0F10A in Nissan's internal nomenclature. JATCO, a major transmission manufacturer, supplies CVTs to numerous automakers. The JF011E is a chain-driven CVT, designed to offer a wide ratio spread and smooth operation.

Key Components and Operation

Unlike traditional automatic transmissions with fixed gear ratios selected by shifting gears, a CVT uses a pulley system to achieve an infinite range of ratios within its design limits. This leads to a smoother, more fuel-efficient driving experience, in theory. Here's a breakdown of the key components:

Input Pulley (Primary Pulley): Connected to the engine's crankshaft.
Output Pulley (Secondary Pulley): Connected to the driveshaft, which ultimately drives the wheels.
Steel Belt or Chain: A multi-link chain or belt that connects the two pulleys, transmitting power between them. The JF011E in the Altima used a chain.
Hydraulic Control System: This system uses hydraulic pressure to control the position of the pulley sheaves (the conical sides of the pulleys), thereby changing the effective diameter of the pulleys. This is the key to ratio changes.
Valve Body: The brain of the hydraulic control system, containing solenoids and valves that regulate fluid flow based on input from the Transmission Control Module (TCM).
Transmission Control Module (TCM): A computer that monitors various sensors (engine speed, vehicle speed, throttle position, etc.) and controls the valve body to achieve the desired gear ratio.
Torque Converter: Similar to those found in traditional automatic transmissions, the torque converter allows the engine to idle while the vehicle is stopped and provides torque multiplication at low speeds.

How it works: The TCM receives information from various sensors. Based on this information, it commands the valve body to adjust the hydraulic pressure acting on the input and output pulley sheaves. When the sheaves move closer together, the effective diameter of the pulley increases. Conversely, when the sheaves move further apart, the effective diameter decreases. The chain rides between the sheaves, and the ratio between the input and output pulley diameters determines the overall gear ratio. For example, if the input pulley has a small diameter and the output pulley has a large diameter, the transmission is in a low gear ratio, providing high torque for acceleration. As the vehicle gains speed, the TCM gradually increases the input pulley diameter and decreases the output pulley diameter, shifting to a higher gear ratio for fuel efficiency.

Simulated Shift Points

While CVTs are inherently gearless, many manufacturers, including Nissan in the 2009 Altima, implement "simulated shift points" to mimic the feel of a traditional automatic transmission. This is done by programming the TCM to quickly step through pre-defined gear ratios, creating a stepped acceleration profile. Some drivers find this more natural and engaging than the constant drone sometimes associated with CVTs.

Advantages of the JF011E CVT

Compared to a traditional automatic transmission, the JF011E CVT offered several potential advantages:

Improved Fuel Efficiency: By continuously adjusting the gear ratio to keep the engine operating at its most efficient speed, the CVT can improve fuel economy.
Smoother Acceleration: The absence of distinct gear changes results in smoother, more linear acceleration.
Reduced Engine Wear: By allowing the engine to operate at its optimal RPM range more frequently, the CVT can potentially reduce engine wear.
Lightweight Design: CVTs can often be lighter than traditional automatics, contributing to improved overall vehicle efficiency.

Disadvantages and Common Issues

Despite its potential benefits, the JF011E CVT in the 2009 Altima was not without its drawbacks. These issues contributed to the mixed reception of CVTs in the automotive world:

"Rubber Banding" Effect: This refers to a delay between pressing the accelerator and experiencing acceleration. The engine RPMs can increase dramatically before the vehicle speed catches up, creating a disconnected feeling. This was a common complaint with the early JF011E implementations.
Premature Chain Wear: The steel chain in the JF011E is subjected to significant stress. Insufficient lubrication, aggressive driving, or exceeding the transmission's torque capacity can lead to premature chain wear and eventual failure.
Valve Body Issues: The valve body, with its intricate network of solenoids and valves, is susceptible to clogging and malfunction due to contaminated transmission fluid. This can lead to erratic shifting, slipping, and failure to engage.
Torque Converter Problems: The torque converter, like in any automatic transmission, can experience issues such as stator failure or lock-up clutch problems.
Overheating: CVTs can generate significant heat, especially under heavy load. Insufficient cooling can lead to transmission damage. Nissan issued service bulletins related to CVT overheating in certain conditions.
Fluid Degradation: CVT fluid is specifically formulated for the unique demands of a CVT. Using the wrong fluid or failing to change the fluid at the recommended intervals can significantly reduce the transmission's lifespan. The correct fluid is essential.

Addressing Common Issues

Many of the common issues with the JF011E CVT can be mitigated through proper maintenance and driving habits. Here are some key recommendations:

Regular Fluid Changes: Adhere strictly to Nissan's recommended CVT fluid change intervals. Use only Nissan-approved CVT fluid (NS-2 or NS-3, depending on the specific model and revision). Early models often specified NS-2, which was later superseded by NS-3, offering improved performance and durability. Verify the correct fluid specification for your particular vehicle.
Avoid Aggressive Driving: Minimize hard acceleration and prolonged high-speed driving, which can put excessive stress on the CVT components.
Check for Leaks: Regularly inspect the transmission for leaks. Promptly address any leaks to prevent fluid loss and potential damage.
Consider an Auxiliary Cooler: For those who frequently tow or drive in hot climates, installing an auxiliary transmission cooler can help to prevent overheating.
Monitor Transmission Temperature: If possible, monitor the transmission temperature using a scan tool or aftermarket gauge. If the temperature exceeds the recommended range, take steps to reduce the load on the transmission.

The Legacy of the 2009 Altima CVT

The 2009 Nissan Altima's CVT experience served as a valuable lesson for both automakers and consumers. While the CVT technology offered potential benefits in terms of fuel efficiency and smoothness, its reliability and durability concerns highlighted the importance of proper design, manufacturing, and maintenance. Subsequent generations of CVTs have incorporated improvements in chain design, hydraulic control systems, and fluid technology to address these issues. While the early JF011E had its flaws, it paved the way for continued development and refinement of CVT technology, which is now widely used in various vehicles across different manufacturers. Understanding the intricacies of the 2009 Altima's CVT provides valuable insight into the evolution of this increasingly common transmission technology.

Proper maintenance and using the correct fluid are absolutely critical to the longevity of this transmission.