Transmission Solenoid: Symptoms & Replacement Cost

Modern automatic transmissions use pressurized hydraulic fluid to change gears. Every time a gear change is required, the car’s computer activates a transmission solenoid, which directs transmission fluid into the valve body to engage the correct gear. If one of these electro-mechanical valves fail, then all sorts of transmission problems can ensue. So let’s take a closer look at the shift solenoid, and the common problems associated with it.

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What Transmission Do I Have?

How Does a Transmission Solenoid Work?

As you’re going down the road, the car’s computer analyzes data being sent by vehicle speed sensors and engine speed sensors. Based on this information, the Engine Control Unit (ECU), or the Transmission Control Unit (TCM), executes the appropriate upshift / downshift by sending a signal to one of several shift solenoids. These transmission solenoids have a spring-loaded plunger inside, which are wrapped with wire. When this coil of wire receives an electrical charge from the TCM / ECU, it causes the plunger to open, allowing transmission fluid to flow into the valve body and pressurize the desired clutches and bands. When this happens, the transmission changes gears and you continue down the road.

The car’s computer can control the transmission solenoid in several ways. If the vehicle is equipped with a dedicated Transmission Control Unit, it can open or close the hydraulic circuit using a direct 12v signal. Or, the Engine Control Unit can control the solenoid’s plunger by turning the ground circuit on and off. A solenoid can be used to control a single gear or multiple gears, depending upon the complexity of the design.
Transmission Solenoid Locations

Symptoms of a Transmission Solenoid Problem

Solenoid A transmission solenoid can fail due to electrical issues, or dirty fluid that’s caused the shift solenoid to become stuck open / closed. Any change in the transmission fluid pressure can cause numerous problems, including:

Erratic Shifting – If you’re dealing with a failed transmission solenoid, the gearbox can skip a gear up or down, shift back and forth between gears repeatedly, or get stuck in a gear and refuse to shift.

Transmission Won’t Downshift – If the transmission will not downshift, one of the shift solenoids may have become stuck open / closed, preventing fluid from entering the transmission valve body to pressurize the correct gear.

Severe Shifting Delay / Stuck in Neutral – In order for an electronically controlled automatic transmission to shift gears, the solenoid must be able to regulate the fluid pressure to activate the appropriate gear. If the shift solenoid is receiving too much or too little electric current, or dirty transmission fluid has caused it to become stuck open / closed, gear engagement maybe become difficult or delayed, which can cause the transmission to act as if it is temporarily locked in neutral.

Because the solenoids are connected to a vehicle’s electrical system, the ECU will usually register an error code and trigger the check engine light if something goes wrong. If this happens, the transmission can go into limp / fail mode, where it will only engage second / third gear to limit the vehicle speed without immobilizing it.

The first thing that your mechanic should look at are the error codes. Using a scan tool, the technician can determine the source of the solenoid’s problem. It could be as simple as a bad ground, or as complex as a failed solenoid pack (a grouping of individual shift solenoids).

Transmission Solenoid Replacement Cost – Parts & Labor

In most cases, solenoids are located inside of the oil pan, connected to the valve body. Depending on what you drive, the technician may be able to replace just the failed shift solenoid. However in some cases, the solenoids come in these multiple unit packs so if there is a problem with one, the entire pack must be replaced. This job typically takes 2-4 hours to complete, and shop time is generally billed at $60 – $100 per hour. The average total cost to diagnose and replace one ranges between $150 and $400.

Depending on the make and model of your vehicle, expect to pay between $15 – $100 for a single transmission shift solenoid. A pack can cost $50 to $300.

TypeCost Range
Single$15 to $100
Pack$50 to $300
Labor$120 to $400
Total (Pack)$250 to $600

Solenoid Pack

Although it isn’t unusual for transmission shift solenoids to wear out over time, you can extend their life by changing your transmission fluid at the factory recommended intervals. This will clean out all of the dirt and sludge that builds up, and the fresh fluid will keep the plungers on the inside of the solenoids from sticking. If you don’t know what your vehicle’s recommended transmission service intervals are, check the back of your owner’s manual, or simply ask Google.

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Need a replacement transmission? Get an estimate for replacement transmissions and local installation. Look up your transmission model by vehicle make and model.

What Transmission Do I Have?


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Daniel L Cox
14 days ago

I have a 1990 Chevy G30 RV/Class B Van Conversion with a 5.7L engine and less than 120,000 miles. As I drove over distance (50-75 miles), the transmission appears to heat up and no longer can shift correctly. I can not get much over 40 MPH with the gas pedal. The funny thing is that it actually would go slightly faster when I used the Cruise Control to manage the speed, though it still did not seem to shift into a higher gear.

John Avant
17 days ago

I have a 2005 envoy I have to shift the gear back and forward to get the transmission to engage in drive and reverse

1 month ago

Needs solenoid pack replacement

1 month ago

Tries to go forward in all gears but rpms are higher then the speed of the car by far. Acts as if it’s slips. But it will go in reverse with no problems. In fact I drove it home 12 miles in reverse. Fluid smell burnt.
.05 highlander. Problems started about 10 miles after working it hard to get up a iced hill last winter. No problem with it before that.

Last edited 1 month ago by Kenneth
1 month ago

I put a different transmission in my 2000 Ford ranger everything worked good and the other day i went to turn around and it just stopped moving like it was low on fluid but it’s not what could be the problem it dont move any any gear

Betty Jackson
1 month ago

I have a 2011 Buick Regal and it was stalling moving slow when I hit the gas, every time I came to a stop. Then one morning it started up and when I shift to drive it would not move, but it does drive backwards when put in reverse. All the other gears work except drive, does this mean transmission replacement???

Ayla Merritt
1 month ago

Just finished install on new transmission, everything lined up right and bolted in and fill of fluid but it won’t come out of park. I’m at a loss! HELPP!! 96 f150 4×4 automatic transmission 5.0L

Last edited 1 month ago by Ayla Merritt
1 month ago

02 durango leaves huge puttle when parked but not while driving of transmission fluid

Kenneth Williams
1 month ago

Drive back from Orlando on new year’s my 2004 Chevy trailblazer made a a poofy sounds there was no more going forward the car would shift just wouldn’t go into any gears

1 month ago

Transmission will not shift out of first. reverse works fine. 4L60E 2006 Yukon

1 month ago

When I come to a stop sometimes, I take my foot off the brake and it seems to just sit for a few seconds before starting to move forward. 2014 vw jetta

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