The Best OBD Scanner for Diagnosing Transmission Issues

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Besides the engine, the transmission is your vehicle's second most important mechanical component. Without a manual or automatic transmission, you and your vehicle are not going anywhere. For the most part, your transmission is very reliable, but problems can develop, such as slipping (most common), not smoothly shifting gears, or not staying in gear as you drive.

For an automatic transmission, these signs can indicate internal damage or the transmission fluid is low. There could be other issues with manual transmission, such as a bad clutch plate, failing throw-out bearing, or low fluid in the hydraulic clutch cylinder.

In this article, I will focus on automatic transmissions and provide you with an overview of how they work, the warning signs of a failing transmission, how to diagnose and fix transmission issues before the damage compounds, and how the cost of repair increases. By actively maintaining your vehicle's transmission system, you can save significant amounts of money on costly repairs, which should motivate and encourage you to be proactive.

How does a transmission work?

At the heart of an automatic transmission lies a fascinating component-the torque converter. This ingenious device allows your vehicle to shift gears seamlessly, without any intervention from you. While most transmissions have four or five gears, some newer models boast as many as ten. This type of gearbox operates using a transmission fluid coupling, with a reservoir of transmission fluid serving as its lifeblood. The complexity and sophistication of this system is truly intriguing, isn't it? It's like a well-orchestrated symphony of mechanical parts working in perfect harmony, inviting your curiosity and interest.

Modern transmissions are controlled by a computer, which selects the correct gear based on inputs from various sensors located around the vehicle. This advanced system often includes an overdrive gear designed to improve fuel economy by reducing engine drag at high speeds. While these technological advancements enhance your vehicle's performance and efficiency, they can also increase ownership costs, especially as the transmission ages.

Let’s take a deeper dive into the various components that make the transmission tick:

• Transmission fluid is the heart and soul of the transmission. All of its internal components depend on the constant flow of the fluid. For this reason, it is important to ensure that the fluid level is maintained and that it does not break down as it ages. A quart of fluid typically costs $8 - $20.
• The transmission solenoid is an electromagnetic component that controls the fluid flow throughout the transmission. If it malfunctions, fluid may not reach the critical components inside the transmission, which could lead to operating issues. The typical cost to replace a solenoid is $500.
• Transmission bands link the internal gears together to ensure the transmission will not slip. As the bands age, they begin to have wear and tear and other damage that could cause the transmission to slip. The typical cost to replace the bands is $1,500.
• The torque converter converts the power from the engine into torque, which the transmission uses to turn the drive wheels and propel the vehicle forward. This is the most critical transmission component, so it is important to protect it by ensuring that the fluid level is correct. If you notice issues like smoking or jumping gears, the torque converter could be the culprit. The typical cost to replace a converter is $1000.

Based on the costs associated with the various components of the transmission, there are a few simple things you can do regularly to identify potential issues and take corrective action. These include checking the fluid level and making sure it is in range. If you see some purple-colored fluid under your vehicle and need to add fluid frequently, you probably have a transmission fluid leak. The other check you can do is run the transmission temperature test using an OBD scanner. This will tell you if the fluid is within the normal operating range, as a high temperature indicates the fluid level is low or is not circulating efficiently.