Transmission Valve Body: Function and Symptoms Warranting Repair

Transmission Valve Body: Function and Symptoms Warranting Repair

When your car has an automatic transmission, valve body is a major component. It works in a network form and functions as a main control center.

The body valve works by directing pressurized transmission fluid to a network of valves that put together appropriate clutch packs, upon which the valves draw pressure from hydraulic signals, determining the gear set (servo).

This process is performed with changing speed processes, in order to provide the transmission system with smooth gear functioning.

Of all of the valve body components, the most important is the manual valve that is directly connected to the gear stick handle, and its main function is to calculate the right passage for hydraulic fluid to pass through.

Nowadays, modern automatic transmission valve bodies come with sensors that measure various transmission aspects like:

  • speed
  • brake
  • pedal position
  • throttle position
  • engine load

Vital information from the components get sent via the sensor to the onboard engine management computer. That further directs the electrically controlled solenoid that redirects the hydraulic fluid to the right clutch pack, guaranteeing a soft and smooth change between gears.

Malfunctioning Symptoms

There are a few transmission valve body symptoms that need to be taken care of properly.

Driving with a faulty transmission valve body is something that affects the driving ability and create havoc when changing gears.

The main symptoms of a bad transmission valve body are:

  • Hearing banging or knocking noises when pressure is applied to the brakes
  • Car slows down when the car is put in reverse mode or driving backwards
  • The shifting stick slips regularly when changing the gears
  • Transmission runs into trouble when downshifting
  • Facing problems while changing your gears to reverse or drive
  • The car’s transmission may get stuck in neutral

Diagnosis and Replacement

The cutting-edge technology of modern diagnostic computers and tools, helps malfunctioning transmission get easily detected. Thanks to advancements in electronics manufacturing services, elements like a PCB assembly help to control your transmission and keep it working smoothly, most of the time. However, mechanical failures and electronic failures are really two different groupings.

You as the driver will immediately notice if anything goes wrong when the car’s dashboard activates a warning light.

Regardless of that, a timely inspection of the transmission valve body should be performed regularly in order to sharpen well-functioning.

When it comes to replacing a bad transmission valve body, cost is something to take into account, as it will depend on the labor and model of your vehicle.

Keep in mind that this, along with the timing belt are the most expensive car part replacements that you will need to make.

An average transmission valve body piece will cost between $200 to $500. In addition, the labor costs tend to be quite extensive as replacing a transmission valve body can take anywhere from 2 to 4 hours to finish. So, it is important to note that the hourly rate of a mechanic fluctuates between $60 to $100. This means that the least you will pay is between $120 and $400 for labor costs before taxes and fees.

Which means that the total cost of the valve body replacement will vary between $320 and $900.

Though being expensive, replacing the valve body is worth the investment, which is better than the thousands of dollars you’ll end up paying to fix the entire transmission system.

Transmission Valve BodyThe replacement system consists of:

  • Raising the Vehicle and jack stands in appropriate support areas to help support the vehicle while you are repairing it. After you have properly positioned the jack stands, lower the floor jack so that the vehicle rests securely on the jack stands.
  • Removing the vacuum hose that leads from the intake manifold to the transmission modulator valve.
  • Pulling the hose off of the intake manifold and transmission modulator valve and checking the hose to look for presence of transmission fluid that might indicate a defective manifold.
  • Removing the defective modulator valve by carefully removing the bolts from the bracket that holds the modulator valve into place.
  • Installing the new transmission modulator valve by placing the actuating rod into the hole of the new transmission modulator valve and then carefully inserting the valve into the receptacle hole.
  • Reinstalling the bracket on the modulator and securing it with the bolts.
  • Reconnecting the vacuum hose to the transmission modulator valve and the intake manifold.
  • Removing the jack stands.

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Bryce Newell is an automotive enthusiast who loves to write about the latest news, products, and DIY projects. While Bryce is an amateur in the field, he is passionate about cars and has been since he spent weekends in the garage helping his dad rebuild a 68 Dodge Charger as a kid.

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