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 99 Silverado Z71 4×4 i bought at a great price with knowledge of the transmission problems… Im hoping to get lucky and it be a minor issue. The truck will not shift into 3rd actually it will not shift past 2nd …reverse works great. I added some fluid and got it to shift into 3rda cpl times. So I drained it to change the filter and fluud because it was very burnt looking . there was lots of sludge build up and some small aluminum dust also but no metal in the magnet one of the solenoids can be wiggled around sand twisred over a 1/3 of a turn… Any help is welcome & greatly appreciated
2002 gmc denali 1500 all wheel drive, temperature gage goes above normal and it’s not shifting past second gear.
Changing solenoids in an 02 GMC 2500hd and can not get the trim A and B solenoids back in
My Pressure Control Solenoid b Malfunction (Shift Solenoid b) is bad and I needed to know what type of engine I have and should I get a pack or just the one Solenoid
2009 Kia Borrego Automatic Transmission.
It started out with the transmission causing the car to jerk pretty hard every now and then when you hit the gas to take off. It progressively got worse and worse. Then after a while when diving it got to where it struggled to shift up to the next gear and to downshift when coming to a stop. Now it has gotten to the point where it will not go in reverse. You put the shifter in reverse and car wont move. It will no longer shift to 1st, 2cond, 5th, or reverse. I can drive it but only drives in 3rd and 4th gear, so it runs the Rpms up to high taking off like that. Also, the plus and minus manual shift beside the D on the shifter doesn’t work. Can someone please help me. Any idea exactly what’s causing this?
Its Christmas time and really cant afford a rebuild or new transmission. So was hoping I could find out what it is and fix it.
Transmission (mustang 06 v6) is slipping when trying to go into 3rd gear and ends up catching into 4th
I have a 2015 Hyundai Sonata with 195,000 miles. While driving on highway, the engine froze up. Car towed to dealer. Hyundai approved having new(rebuilt) engine installed at no cost to me. After dealer installed, they told me that the transmission was frozen in 4th gear and it would cost me $2,800 to repair. I questioned whether frozen engine caused it or possibly transmission damaged during extraction or installation of new rebuilt engine? They said there is no way that either could cause this problem with transmission and it was simply coincidental that my car was stuck in 4th after engine replaced even though I had no transmission problems previously.
Question: could an engine that freezes up on the highway cause transmission to get permanently stuck in 4th and/or could the removal or installation of new rebuilt engine by authorized dealer have cause this transmission problem? Thanks!
Bump when shift from D to R
chucks when engaging in 4 wheel drive when trucks moving doesn,t do it when stopped
It started with a dtc trans pressure low. So I did a fluid change and filter and now it won’t even go into gear. The fluid is bright red and I’ve probably over filled it thinking that maybe I drained more then I thought!! Now , it won’t even throw a code so I’m going after the pressure switch and anything else I can find to see where the problem is
Any solution? Having the same problem with my 2006 sienna van.
Shift from drive To 3rd it doesn’t change lost the drive what the fix
Lost the drive, when I shi3rft into 3rd no change like it’s still in 3Rd gear
2004 Acura tl. Installed rear motor mount. Upon completion of task car starts out slow while revving higher than normal until eventually getting up to speed. Performs normally if manually shifted from 1st through Drive. Innova 5610 OBD2 reader shows codes of P0974 (shift solenoid A control circuit high) and P0980 (shift solenoid valve C open Valve C high impact). Fluid is dark. Worked fine before motor mount repair. Wiring to the dual linear shift solenoid had been cut or torn during repair and twisted back together covered with electrical tape .I purchased a new dual linear shift solenoid and replaced the old one. 3 new O rings installed as well as cleaning the screens on the 3 tubes. Also installed new gasket. Haven’t changed fluid yet. Same symptoms after repair. Wanted to get further advice before proceeding. Car shifted smoothly prior to motor mount swap by an obviously untrained person. Now I’m stuck with it. Plan on draining the tranny fluid and refilling with fresh (I’m guessing about 3 quarts at a time. Then running down the road to bring it up to operating temp. Repeating the drain and fill 3 times, but not flushing. At least that’s the method some guy posted on YouTube. Again, wanted to get further more professional advice before proceeding with that idea). Also, not sure of location for solenoids A and C. Any help would be greatly appreciated. Car is my sons. Worth $1500 on a good day. Just trying to revive it for him so we don’t have to keep running him back and forth to work. Thanks again.
I have a 2005 chrysler town and country. When I put it in drive it barely moves. Come to a complete stop, put it in park, turn off the engine, restart the van and it will go but will again do the same thing. I changed the transmission fluid, filter, and the input and output sensors but it’s still doing the same thing. It’s throwing codes p0700, p1775, and p0734.
1996 F150 4r70W AODE transmission. After driving a while the engine will start missing and backfiring. It will not go more than 30 mph with the pedal to the floor.
F150 3l3p transmission hard shifting 2004 model
F150 3l3p hard shifts
I have a 1996 Chevy Cheyenne 1500 2wd 4.3l Automatic transmission and I have put a used motor in it cause I forgot to check the oil in it one day well after that it seems like my transmission wants to fall out. Cause when I have to come to a stop mostly on small hill I have to put it in low gear meaning 1st gear well when I shift up to 2nd gear nothing happens no jolt or nothing but when I go from 2nd gear to 3rd there is a jolt and my truck takes off like it’s supposed then. Would be cause of a bad solenoid switch? Oh and I have changed the transmission fluid like 5-6 months I know I need to do it again.
i got a computer read out that said shift selenoid c was bad on my ford focus, so this weekend i replaced it, an since i had the pan off, i replaced A and B also, i waited 24 hours and put fluid in it, let the eng warm up shift it through the gears in my drive way, waited a bit and the little wrench came back on, and the check eng light. so i put it in reverse an backed it out of my driveway an it went fine, when i put it in drive, it wont go, when i put it in first, it wont go, before i replaced the selenoids the car would go through 1st and 2nd, but wouldnt go into drive
2003audi a4 only has reverse
My 2007 caravan is not going into reverse all the way ,but has that this noise, my forward drive is fine, my question is it a soleid problem?