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?
Change silnode on shifter
I have a 2004 grand prix I had a transmission cooler line leaking so I got that fixed and a couple day later when I put it in drive it takes a minute for it to catch up…what can be the problem
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my 2005 impala has shifted hard and sometimes even felt like it was slipping ever since i owned the car it had 158k when i got it now 2 yrs later shes still going with 210k i have the shift solenoids for it but i want to see if the trans out of my 02 Buick la saber will fit my impala
No power when you step on the gas pedal
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my transmission won’t engage the reverse it was was leaking fluid from the cv axle seal ring .replaced the cv axle and refill the fluid transmission ,still didn’t fixed the problem. Should I replace the shift selenoid or what should I do next
I have it “rebuild” and never worked. I get code P0745, 741, 733, 734 & 1000. It would work fine for 3 mnts. And then get stuck in 1st. Gear.
Was told ‘03 Avalon shift solenoid B is stuck open. Replacing of solenoid pack was recommended for $900-$1000.
Check engine light is on but no noticeable symptoms while driving.
2006 ford fusion wint shift at times what could it be
Wont shift then will shift fine
2011 Hyundai Elantra 1.8 L 4 cyl 6 speed transmission goes into limp mode have to stop and restart engine to get it to drive. shifts fine up to about 30mph.
I have a 2011 Chevy equinox and goes down the road and stops or goes back to neutral and won’t go no where and wit a few min and start it up and it will go and do it again
Will run and go down road and stops pulling stop wait a few and goes down the road and continue problem help solinoids. And still having same problem
When i put it on drive or neutral it dont do anything but rev the engine, i changed transmission fluid and still nothing. I took off the shift sensor but seems to be fine, dont know what else, i have a 2000 honda accord.
I have a 2004 Pontiac Grand Prix GTP and I rebuilt the transmission It’s a 4T 65E I have been rebuilding transmissions for years I’m getting a code 1860 A code I never had before but the transmission worked fine why didn’t like the engine light on so I put a new lock up solenoid in it And now I don’t go in the lock up at all and my tap shifters don’t work I know it’s got to be the electrical problem I pulled the pan back off the side pain and looked at everything and everything seem to be normal I used an OHLM meter and everything checks out I’m stumped.
When the transmission shifts into 3rd gear its a hard shift jumps forward
My 06 honda shifts hard from 2to 3 but after that it won’t shift in to overdive and it won’t downshire
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