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.
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.
Symptoms of a Transmission Solenoid Problem
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.
| Type | Cost Range |
|---|---|
| Single | $15 to $100 |
| Pack | $50 to $300 |
| Labor | $120 to $400 |
| Total (Pack) | $250 to $600 |
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.
Get a great deal on a replacement solenoid – for as low as $11 on Amazon <
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?
My transmission slips in reverse only, what’s the problem and can it affect my forward drive?
4R70W transmission. Goes into reverse but wont engage into any forward gears. Goes into forward gears. But wont move. Reverse works fine
I have a 91 Ford Ranger XLT 4×4 , seems to be stuck in low gear . All gear are forward think that is fixed
But I can’t find what type of tranny it is
Reverse dont always work
My truck said that the transmission was hot then it went into limp mode the fluid not low and I reset the computer but its stuck in limp mode what do I need to do to fix my truck I have a Chevy 1500 z71
Toyota Tundra SR5 2004
Blowed a trans coolant line and got it fixed refilled the fluid now it won’t go into R and N acts like D
2002 Dodge Ram 1500 van.
Trans temp light comes on then not down shifting and sluggish.
Transmission has delay when shifting 2 to 3. Light came on said 2nd shift solenoid.I cant remember the code that came up for the life of me but was only that one code. Changed all solenoids,did a flush,new filer,gasket and fluid but still having same issue with 2/3 shifting. Ive drove it a few times to see if code would come back on,no results.Any help would be grateful.2004 chevy Silverado 5.3 vortex 4L60e tranny. Thanks
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.
I have a 2005 envoy I have to shift the gear back and forward to get the transmission to engage in drive and reverse
Needs solenoid pack replacement
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.
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
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???
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
02 durango leaves huge puttle when parked but not while driving of transmission fluid
You gotta get under it and just look at it. Would you just look at it… try your best to find directly where it’s coming from. Can’t find it, then clean oily area on transmission then check again. Find the leak, use Google assistant or whatever in assisting you on what part or seal may be leaking if possible. Then Google some more. It’s best not to read threads because people are dramatic and most are full of there mom and dad, idiots. I trust you can find that leak and possibly fix it.yourself. If not yourself then you’ll know what’s wrong and possibly save yourself from getting ripped off at a shop. The more you know.
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
Transmission will not shift out of first. reverse works fine. 4L60E 2006 Yukon
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