Flex Plate – What Does It Do and What Are Signs of Bad Flex Plate?

Brandon Trenton

What is a flex plate

With a recently discovered quintessential use, the flex plate has brought efficiency and reorganization in the motor vehicle arena. Emerging as a streamlined counterpart of flywheel, flex plate is a beneficial device for vehicles featuring an automatic transmission system.

Positioned amidst the engine, the gearbox, and the transmission instrument, it serves the main purpose of storing and processing the energy produced by the engine of a vehicle. While early vehicles embraced flywheels, owing to the latest mechanism efficiencies, the flex plate has entered the picture. This article walks you through several aspects associated with this handy device.

The Process Of Working Of Flex Plate- From A To Z

Performing a major part of the job involved in running a motor vehicle, this robust technology transfers the energy required to run the wheels of the automobile and, ultimately, commence its movement. Sourcing and accumulating the energy transferred from the engine, a flex plate relocates the energy through a gearbox, i.e., the transmission system of the vehicle.

Engines Generate the Initial Power in a Vehicle

The original source of power generation is the engines. Even though the power generated is potent enough to run the vehicle, it is not perpetual and persistent enough to ensure even running of the vehicle. The process of internal combustion is quite irregular and thus needs to be administered before being transferred to the transmission mechanism. If the same is not done manually or automatically, the movement of the vehicle will be rather abrupt.

Flex Plate Start Storing this Energy Produced by Engines

After the engine produces mass-energy, the flex plate or the flywheel initiate their job and start storing the energy produced. This is executed by the spinning of the plate at a high pace and an even speed. The next step entails the transfer of this piled-up energy to the transmission box.

This Piled-Up Energy Is Then Transferred to the Transmission Box

If the vehicle is manual, the clutch is used to accomplish this; otherwise, a system called torque converter is used. This mediator assists in the transfer of the output from the engine and its further transmission to the gearbox unit. The arrangement of the elements is made in a manner to ensure a seamless shift of energy.

Prominent Differences Between Flex Plate And Flywheel

Even though bearing the same purpose, flex plate and flywheel have their share of differences. Both these devices perform the very vital function of leveling the energy generated by the engine to ensure that the vehicle rides fluently. The most apparent difference exists in the designs of these systems.

System Design of Flywheel

The flywheel is an inertia device fastened to the engine crankshaft. The basic role entails carrying and storing energy from the engine to transfer it in an even manner for the movement of the vehicle. Since it is involved in the conventional mechanism, a flywheel also embraces a frictional surface to hold and clasp the clutch disc.

System Design of Flex Plate

For the flexplate, the function remains identical till the mounting of the ring gear to the starter to crank the engine. The contemporary system involves the use of a flex plate to provide a backing system to a torque converter, which is a counterpart of the clutch disc. Serving as a connection between the engine and the transmission, a torque converter enables the movement of the vehicle from a standing point in case of the automatic transmission system. A flexplate does not feature any friction surface as the use of the clutch is not involved.

While the flex plate is lighter in weight than a flywheel, it also contains holes that ensure that the plate remains mounted and is properly fitted with the torque system. Also, a flex plate upholds a major task of maintaining and facilitating the balance of a vehicle. Therefore, whenever removed, the plate should be positioned in the exact same spot.

What Does the Word “Flex” Imply?

“Flex” in “flex plate” implies the flexibility featured by a flex plate, unlike a flywheel. While flywheel is a stiff, solid, and heavy device fitted inside a vehicle, a flex plate is thinner and lighter in structure with a considerable amount of flexibility. Constituted by a fine and slender impressed steel sheet, the flex plate’s adaptability to misalignments is well taken care of by its designs. The rigidity of a flex plate can lead to cracking of the plate and impairment of the adjacent parts in the process.

However, it is not possible to bend a flex plate manually as it requires the immense power generated by the engine, which initiates its movement. Also, in conventional systems that encompass the use of a flywheel, such flexibility is not required as the clutch disc disengages the device from the engine whenever the gear is manually changed.

How To Detect Issues With A Flex Plate?

While mechanic experts easily point out any fault with the flexplate, the same is not as seamless for a non-professional. So, here are a few signs that are prominent and point towards some defects in the flex plate of your vehicle.

  • The noise made by the starter motor when the engine is started says a lot about the condition of the flex plate. If you hear a whining sound when the flex plate spins, there exists a good chance that the plate is faulty.
  • If you hear a recurrent dull sound, as if heavy metal objects are striking, when you put the engine on neutral, it shows that the flex plate is in an angular position. This can be caused due to the loosening of the bolt, which further brings the plate in contact with other metal parts of the vehicle, leading to the clunking noise.
  • If you feel tremors in the vehicle, which are otherwise unlikely, there might exist some issues with the flex plate. These vibrations tend to become more vigorous as the vehicle gains more speed.

Other Flax Plate Faults That You Might Encounter

Some of the problems involved in the working of the flex plate can only be detected by a specialist through proper analysis at a workshop. Some of the most common apparent problems observed with the flex plate and their causes are as follows.

  • There are times when either the engine or the torque converter is dislodged, and this leads to loss of balance of the vehicle.
  • The starter drive might be faulty, which causes early wear down of the ring gear.
  • Sometimes, the bolts of the flex plates do not synchronize with the settings of the torque convertor.


Substantially different from a flywheel, a flex plate has managed to create a niche for itself in the automobile industry thanks to the invention of the automatic transmission system. Even though proving to be indispensable and immensely effective, flex plates fail at times due to different discrepancies.

Considering the technical nature of this device and its vitality in running the vehicle smoothly, it is suggested that the problems should be detected and resolved without delay through trained mechanical assistance.