Your car's transmission relies on shift solenoids to help regulate the transmission fluid flow through the gears and transmission components. The plungers of those solenoids spend their entire usable life submerged in that fluid. Over time, the persistent exposure to particles and metal dust can lead to complete failure. Here are some things you should know about failing shift solenoids.

Common Indications of a Damaged Solenoid

If you're not familiar with the role of a shift solenoid, you may not know what happens when one fails. Luckily, there are a few key things you can watch for that may help you to identify the solenoid as the source of your problem.

• Lost Gears – When a shift solenoid stops working, it interferes with gear selection. It might start out with the loss of one gear, meaning that you aren't able to physically shift into a specific gear. In more severe cases, or as the problem worsens, you may find yourself completely unable to shift at all or without several gears.

• Limp-In – Most newer transmissions are equipped with a special mode that allows you to travel slowly and in one single gear to get your car to a mechanic. If your car is locked in this one slow-moving gear, usually second gear, it's typically what's referred to as limp-in mode. The intention is to allow you a forward-moving gear without causing more damage to the transmission than it has already sustained. This engages when the car's computer disables the transmission for an electronic, computerized or other sensor problem. You'll recognize limp-in mode by a heavily limited acceleration and sluggish response when you hit the gas despite slow moving forward.

Tips for Testing the Shift Solenoid

If your transmission is dropping gears or has engaged limp-in mode, it's important to get to the bottom of the issue. The best way to determine if you have a shift solenoid failing is by scanning the OBD-II code from the car's computer. This code tells your mechanic about any faulty sensors and some other issues.

To scan the code, take your car to your local auto parts retailer or your mechanic, like Malibu Motors Service. They can plug the scanner tool in to the computer port in your car and scan the trouble codes stored in the computer's memory. The mechanic can then decode the trouble code to tell you precisely which sensor or component is returning the error. This can save you thousands in troubleshooting costs.