What is a Transmission Shift Solenoid & Why Does it Matter?
When you’re dealing with automotive problems, it can feel as though you’re hearing a foreign language. AWD, gear ratios, oxygen sensors and valves galore may make it hard to have a solid grasp of what the exact issue is with your vehicle. One term that often raises more than a few questions is a transmission shift solenoid. What exactly is it and why should you know about them?
What’s a Transmission Shift Solenoid?
In automatic transmission vehicles, the shift solenoid shifts the vehicle’s gears for you. Your car’s computer, specifically the transmission control unit, takes information from the engine, speed sensors and other parts of your car to determine the best time to shift gears for power, fuel efficiency and similar aspects of operation. When the control unit determines that the transmission should be shifted, it sends power or a ground to open the shift solenoid so that transmission fluid can flow into the valve body. This causes the vehicle’s torque converter to change hydraulic pressure enough to shift gears. But because these are electro-mechanical parts, they can fail, making it impossible for your car to shift between gears.
Why Should I Know About Them?
Shift solenoids can be somewhat expensive to replace, but not nearly as much as the entire transmission. Ignoring a warning light or code being thrown by a faulty transmission shift solenoid can lead to serious problems, such as running your vehicle in the wrong gear for your speed and conditions. This can then lead to your transmission overheating and breaking down.
The easiest way to tell is by paying attention to your dashboard warning lights, typically a Check Engine light or Transmission warning light. You may also notice that your vehicle has shifting delays or that it refuses to shift into higher gears altogether. These issues can also be caused by faulty wiring or shorts in your vehicle’s electrical system.
In some situations, a transmission fluid replacement or transmission flush can free up a shift solenoid that has become stuck, helping you avoid higher repair costs. Transmission torque converter replacement could also be an option, depending on what exact parts are malfunctioning. Though it can be tempting to try to repair a bad shift solenoid at home, it’s recommended that you use an experienced shop to diagnose and repair the issue. Why? If the problem is in the wiring, simply replacing the shift solenoid will not fix the problem. In most situations, you’ll need to remove the transmission fluid pan to reach the solenoid, and in some vehicles, you’ll need to replace the entire solenoid pack to fix the problem. You’ll also need to replace the transmission filter and fluid at the same time.
If you’re concerned that recent loss of power in your vehicle may be related to issues with your shift solenoids or your transmission in general, it’s important to have the problem investigated quickly, before more damage can take place.