How to Troubleshoot a Transmission Shift Solenoid & Gear Shift Lever Indicatorby Mitchell Brock
The gear shift lever indicators tell you what gear you have an automatic transmission in on your vehicle. The shift solenoid tells the transmission when to shift gears and what gear to shift into. Newer model automatic transmissions have electronic shift solenoids that are activated and change gears based on the speed the vehicle is traveling. Troubleshooting either one of these transmission components is relatively easy if you know a little about automobile mechanics. With the right tools, you can determine whether the transmission shift solenoid is having a problem. Gear shift indicator problems can be determined simply by moving the gears into their designated position.
Transmission Shift Solenoid
Raise each corner of the vehicle up with the car jack and place jack stands under the frame. Make sure the car is raised high enough so you can work under the car freely.
Slide the drain pan under the transmission fluid drain plug. Remove the drain plug with a ratchet and socket, and let all the fluid drain out of the transmission. Remove the transmission pan bolts with a ratchet and socket. Pull the pan away from the bottom of the transmission, revealing the transmission shift solenoid.
Wipe off the shift solenoid with a shop towel. Disconnect one of the two plugs that attaches to the shift solenoid. Turn the knob on the volt meter to the ohms setting, so resistance can be measured. Set the volt meter on 200.
Take the black lead of the volt meter and touch the negative battery terminal wire. Take the red lead of volt meter and slide the tip into the terminal plug you just disconnected from the shift solenoid. Look at the reading you get on the digital display of your volt meter. Determine if the reading is between 12 and 25. Readings below 12 or above 25 tell you that the shift solenoid is not working. Reattach the plug to the shift solenoid and pull the second plug attached to the solenoid. Perform the same procedures on this plug wire. Replace the transmission shift solenoid after determining it is bad.
Gear Shift Indicator
Move the gear shift into the desired gear. Look at the gear labels and the arrow, or other indicator, to see if the gear shift indicator lines up with the selected gear.
Move the gear lever to another gear and look to see if the indicator lines up with the selected gear. Misalignment of the arrow will tell you if there is a problem. Moving the gear shift to "neutral" but having the indicator show the transmission is in "drive" tells you the gear shift indicator is not working properly.
Try each gear position to determine how much misalignment is in the indicator. Slide under the car and check for a loose gear shift cable. Check all the gear shift cable connections to ensure they are all tight and are not missing. Tighten any loose gear shift cable clamps or bolts. Replace the gear shift cable if you find that this is causing the misalignment with the gear shift indicator.
- The lead tips on the volt meter and the terminal plugs on the transmission shift solenoid must be clean or you will get a false reading.
- Other possible problems with the gear shift indicator are a misaligned gear shift linkage, loose linkage or damaged linkage. Replacement of the gear shift linkage must be done by a qualified automotive technician to ensure the linkage is installed and aligned properly.
Things You'll Need
- Jack stands
- Ratchet and socket set
- Drain pan
- Shop towels
- Volt meter
- Park the vehicle on a flat surface before raising the automobile and placing jack stands under each corner.
- Ensure that the jack stands will hold the weight of the vehicle and that the automobile is resting securely on the stands before you crawl underneath the car.
Mitchell Brock has been writing since 1980. His work includes media relations and copywriting technical manuals for Johnson & Johnson, HSBC, FOX and Phillip Morris. Brock graduated from the University of Southern California in 1980, earning a Bachelor of Arts in English.