What Is A Transmission Solenoid?

January 14, 2021 | By Mister Transmission

What Is A Transmission Solenoid?

The “transmission solenoid”. Or maybe you heard it as “solenoid pack”. Drivers often hear of this for the first time when something’s gone wrong with it. But just what is a transmission solenoid?

What Is A Transmission Solenoid?

The transmission solenoid is a type of electromechanical valve that controls the flow of fluid. Specifically, in an automatic transmission, we mean the flow of automatic transmission fluid into and through the transmission. In modern transmissions, the transmission solenoid generally comes in a pack which is installed in the transmission control unit, the transmission control module, or a transmission valve body. Transmission fluid is critical to the function of the transmission. If its flow is impeded or hindered, your transmission cannot operate properly.

How Does The Transmission Solenoid Work?

Transmission solenoids are powered by an electrical current supplied by the transmission controller or computer. This is how it works: the transmission computer sends out instructions to the individual transmission solenoids in the pack which then direct transmission fluid to specific clutch packs or servo valves in order to control gear shifting to suit the given driving conditions and engine requirements. A transmission solenoid generally consists of nine parts that all must work together in order for your transmission to properly operate. The nine common parts are:

  • The valve body
  • An inlet port
  • An outlet port
  • The solenoid coil body
  • The coil winding
  • Lead wires
  • A plunger or piston
  • A spring
  • An orifice

What Does A Transmission Solenoid Look Like?

The solenoid body is generally made of steel and it has a cylindrical shape. Transmission solenoids have a valve and return spring in them. The solenoid coil consists of wire wound around a conductive component that acts as an electronic magnet. Controlling the valves position.  

What Happens When A Transmission Solenoid Goes Haywire?

If your transmission solenoid is not operating properly, you are going to have problems shifting. Often this is caused by an electrical malfunction. When this happens, the transmission solenoid acts erratically. In modern vehicles, an electrical or computerized problem should result in the Check Engine light illuminating. However, this is less likely if you are dealing with a mechanical failure.

What Are The Symptoms Of A Transmission Solenoid Problem?

Some common transmission solenoid problems include:

  • A Delay in Shifting
    A common delay will only be a few seconds, but it can be as long as over a minute.
  • The Transmission Refuses to Downshift
    A properly functioning transmission automatically downshifts as it slows down. With a malfunctioning solenoid, however, your transmission might downshift uncontrollably or not at all.
  • The Transmission Shifting into the Wrong Gear
    A defective solenoid can cause your transmission to shift into an incorrect gear.

Mister Transmission

Please contact us to learn more about transmission solenoids.

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Albert Wilton
Good and friendly and reliable people and they work hard to get your vehicle doneService: Transmission
Date: July 25, 2021
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Thank you, Mister Transmission! After...
Christy McMurray
Thank you, Mister Transmission! After taking my vehicle to the dealership where I bought it, and paying $150 for them to tell me what I already told them was wrong, the Dealer gave me a quote of $6,500 to replace my 9 year old transmission with a factory rebuilt one, because it couldn't be fixed or rebuilt by them. Thankfully I called Mister Transmission and Chris knew exactly what the issue was, how to fix it, and it only cost me $385 for everything and it was fixed in a day. I am so grateful that Chris and Dawn run an honest operation and provide genuinely great service. Thanks again!
Date: July 25, 2021
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Cambridge Mister Transmission was awesome....
Sarah MacArthur
Cambridge Mister Transmission was awesome. We ended up having a small issue but they still took the time to show me where on my vehicle the problems were and fully explain the possible issues. They were prompt in getting back to me the following day and I had my vehicle back in no time. Chris and Nick were amazing and the office is so clean and pleasant. Great customer service!
Date: July 24, 2021
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Great service , friendly and...
John Neven
Great service , friendly and very knowledgeable.Excellent work
Date: July 23, 2021
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Mazda 3 AT light came...
Chris Elmquist
Mazda 3 AT light came on one with some bad noises and clunking. Dealer said need a new transmission for only $4400. Took it to this and a quick check they determined it needed new TCM which is very common on the mazdas. They took care of it and even did a bunch of extra work fixing a wiring harness all for the cost of the TCM . cannot say enough about how we were treated by Chris and Dawn. Would recommend them. FIRST CLASS!!!!!
Date: July 23, 2021
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Workers are very nice and...
Ely Bolivar
Workers are very nice and explain thing clearly. Also they have an option to finance your repairs.
Date: July 22, 2021
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They assessed the problem quickly,...
Colleen H
They assessed the problem quickly, quoted a good price, provided fast service, in a no-pressure, friendly manner. I've been telling everybodyService: Transmission
Date: July 20, 2021
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I took my differentials down...
Kieran Massicotte
I took my differentials down to get rebuilt and Steve was very professional and the total was 200 bucks cheaper than the quoted price and there was a few things during the whole process that didn’t go as planned as I had brought all the bearings parts and some bearings were the wrong ones and I had brought 4.88s to put in end they would not work and before continuing with anything Steve would call and double check to let you know what needs to be done and get the ok from me first before they would continue overall amazing place Steve and the guys were awesome and the work was done perfect and the diffs have never been more smooth highly recommend.
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Excellent customer service.Service: Transmission
Eduardo Vieira
Excellent customer service.Service: Transmission
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Thank you Kyle and the...
Roman Danko
Thank you Kyle and the Mr. Transmission team for very professional and friendly customer service and repair. I definitelly recommend their services.Service: Transmission
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