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?
i have a 98 Lexus ES300 that started with a delay advancing (shifting) when taking off from a stop & my rpm’s would go all the way up into the red area. Then with no warning, i parked in a parking lot & when i wanted to leave, the car had no reverse at all. So i tried to go to the junk yard a few miles away & my car refused to shift at all. It would not go more than 20 miles per hr. The engine just revela up as if it were in neutral. So i had it towed back home & when i tried to park it, it wouldn’t move at all.
Slips on take off. Too much gas makes it slip . hanges up between gaers
Is what I got in it started up go down the road it will ship in the high it stays at one year and one gear only it happened just like that nothing out of the ordinary started up wouldn’t shift you got my ship valve ship modular valve
Whe im driving for about 20 min the trans starts slipping and I have to let the gas pedal go and it goes into gear
I have a 2010 f250 when water temp comes up the trans goes to c and will not shef
2007 Kia Optima…..I was driving and all of a sudden it was like I put it in neutral. Reverse still works fine , however NO forward gears do….help!
2011 equinox not shifting into 3 or 5 gear.
Error code PO776 shift solenoid stuck.
Would it be worth changing the solenoid first or the whole trans.
It’s the solenoid pack , not the whole transmission… somewhat easy fix . You don’t need to change the transmission
Don’t pick up no speed
Have 2006 trailblazer ls sport utilty..will not hit 2nd gear..all other gears work fine
TRANS NOT CHANGEI.NG FROM LOW TO HIGH GEAR
1996 chev s 10 auto Tran.wants to shift from 4over drive to 3rd when I let off the gas to slow down when I app.the gas again the rpm show increase the it will shift back into 4th it happens all the time eve. At lower speeds can anyone give me some help
My transmission down shifts when it is between 55 n 60 mph
1994 chevy silverado k2500 4×4 350tbi 4L60E. I have no gears at all. No check engine light on.
i need to know the wiring on the valve body on a as69 transmission
I have a 2003 cadillac cts 3.2L I have a code p0762 when ran by shop told that the shift soleniod c is geting stuck. How hard is it to change out the solenoid packs
Going down a hill and then when trans starts to work again seems like there is a small hesitation and feel like clunk and then it is ok
Why
1997 GMC C1500, 5.0 li engine, transmission wouldn’t shift until 2500 to 3000 rpm after letting off the gas. I have no reverse at all. There was no indication of problems, just stated out of nowhere.
So I just changed my transmission in my 2004 f150 XLT with a 2002 Lincoln Town car same swap I had to change the gear shifter box and the speed sensor now when I put it in drive it’ll drive it’ll reverse but it’s sputters when I step on the gas and it does not downshift at least I don’t think it does it feels like I got a spark plug missing but I just changed four of them and I got four more to go
2000 Ford Ranger overdrive light flashing on dash losing power engine revving
Overdrive light keeps flashing on and off delayed shifting engine revs losing power surging power
1997 Avalon the car drives perfect it shifts just fine CHECK ENGINE LIGHT is on and it says its the shift solenoid e…
2017 F250 6.7L Super Duty 4wd -Trans doesn’t shift over 3rd gear. TDCs P0771 and P2704.
2004 pontiac grand am now in limp mode, p0758 code, shift selenoid b, j reset the comp, car starts in 1st, shifts to 2nd, attempts 3rd, fails and back to limp mode. What now
In limp mode no speedometer or rpm gauge changed shift Solenoid transmission has no power