Flex Plate Installed Backwards: Will It Hurt My Car?

What happens with a flex plate installed backwards: does it work fine or can it damage the car? Let us find out.

A backwardly installed flex plate might cause severe damage to the engine, gear, and transmission system. The good thing about the scenario is that you would almost immediately notice if you have installed the plate in the wrong direction due to the various sounds generated by the rough-running engine and the gears.

Flex Plate Installed Backwards

What Is A Flex Plate?

A Flex plate‘ connects the automatic transmission with the rest of the transmission system. It acts as a connecting link between the torque converter and the clutch in a transmission system.

It is a disc made of metal that is anchored to the crankshaft of your car. A Flex plate transfers the engine’s energy to the torque converter. As the name suggests, the essential plate can flex and accommodate the moving torque converter. The plate flexes or bends from the sides when the wheels of the converter are in motion.

A Flex plate is much thinner and lighter than old-school flywheel manual transmitters and the clutch. So, the overall coupling with the torque converter is smoother in the case of flex discs.

A Flex plate and the starter motor are coupled together through the teeth on the plate’s corners.

How To Install A Flex Plate?

Installing a flex plate is a challenging job. It would help if you did all the heavy lifting, and the work needs to be precise. Doing the job without help or expertise results in various issues, such as Backward installation.

Experts, therefore, advise you not only to take the risk if you are used to such a job. But if you’re confident enough, follow their steps and collect the important equipment: a voltmeter, a floor jack, a wire brush, flex plate turning tools, etc.

Remove the flex plate

The first step that you need to do is to remove the old flex plate. Before removing it, inspect it. Take a close look and see if the damages are repairable. The damage could be localized in mechanical or electrical parts. You need to repair the part that damaged your flex plate, as it would do the same damage to the new flex disc.

Flex Plate Installed Backwards

Prepare the surface

The number one rule of automobile installations is to clean the surface of the attachment before installing it. Similarly, you must clean the surface of the crankshaft thoroughly, preferably with a wire brush. Clean the fasteners as well so there is no obstruction when installing the flex plate. You need to ensure that the flex plate can move smoothly over the diameter of the crank. You should place the flex plate perfectly against the crank.

Match the flex plate

The next step is where precision is required. You need to align the flex plate and the torque converter together. Flex plates are manufactured to be unique to a particular vehicle model. The confirmation of a flex plate changes with the model, manufacturer, and generation of a vehicle.

So while replacing the flex plate, you should keep the holes for the bolts lined with that of the torque converter. Additionally, you must ensure that the torque converter pads lie flat on the crankshaft and the flex plate.

Fix the flex plate

Now it’s time to fix the flex plate on the crankshaft. You can fix the plate by using a thread locker which you can find on the crank bolts. Keep the converter and the front pump handy, as you would require them for clearance.

If you think the clearance is too big for the purpose, then you can use shims. Shim is flat and is consistent throughout the converter pads.

What if the clearance is too small? When the clearance is smaller than required, the machine raises its clearance.

Clearance is a crucial step in the entire process, as severe issues might occur if it’s not done properly. The converter and the flex plate are around ⅛ of an inch away from each other in most models.

Install the starter

Once you are confident that all the components are properly affixed, ensure the electrical parts are well connected. It would be best if you made sure that no wire was loose. After checking all the components, you should connect the transmission and the converter. At last, you should install the starter in your automobile.

To watch the process, look at this video:


How To Not Install A Flex Plate Backward?

Often car owners end up installing a flex plate backward. To avoid this common mistake, follow the tips given below.

You can find a lip with a height of about 1/16th of an inch at the flex plate that attaches itself to the crankshaft and makes it impossible for the plate to go against the crank. If you see that your flex plate is standing flat against the input shaft, then be sure that you have installed it backward. The plate also possesses a dowel pin meant for indexing the flex plate.

While installing the flex plate, ensure its balance weights toward your engine. Remember that the bolt pads on the torque converter should face the converter itself. So, if you keep two things in mind: one is to place the lip of the flex plate correctly, and the second is to ensure the correct position of the bolt pattern.

Flex Plate Installed Backwards

You can easily tell if you have installed your flex plate backward by looking closely at it. Backward-installed flex plates will have indents facing the other face, not the engine, which is wrong. Remember that the indentions of the plate are not meant to face the converter.

If you are facing a problem fixing the flex plate through the bolt holes, you should see everything you have done and check whether you have installed the flex on the wrong side. It won’t be a tedious process, as all you have to do is to slide the transmission. You must have enough space to allow the flex plate’s free movement.

You would require a long crank or a spacer attached to the lip of the flex plate to ensure proper fittings of the plate. Proper fittings are crucial for the free movement of the plate.

What Will Happen If You Install A Flexplate Backward?

The flex plate you installed backward is not only non-function but also poses severe damage to the engine. Some of the Consequences of a Backward flex plate are listed below:

  • The displaced lip will result in the bending of the flex plate due to torque in the bolts of the crankshaft. The flex plate can become deformed and difficult to reinstall.
  • In some vehicles, the engine remains balanced on a bench. A backward flex plate will disrupt the balance, which will cause serious problems as the flex plate is associated with the torque converter.
  • If you install the flex plate backward, the distance between the starter gear and ring gear will not allow them to engage with each other. Or the ring gear could be too close that disengagement will be a problem. The distance between the ring gear and the starter should be precisely 0.1 inches, which might vary within 0.4 inches. A backward flex plate often ends up damaging the ring gear.
  • If you install the flex plate backward, there is a high risk of damaging parts, the entire transmission system, and the gearbox.

You will notice a knocking sound when you install the flex plate backward while engaging with the gears. So you would almost immediately know that something is off about your installation.

Flex Plate Installed Backwards

How Do You Know That You Have A Damaged Flex Plate?

The following are the symptoms of a damaged flex plate:

  • The starter with stop working, and it will face difficulty while turning.
  • You will hear whining sounds from the starter.
  • The engine will make a chirping and grinding noise, indicating that it is running roughly.
  • Whenever you engage with the gears, the engine will knock.
  • There will be too much vibration when the car is moving.
  • You will notice that much power is lost while driving at a higher speed.

Frequently Asked Questions

What can damage a flexplate?

If you install a flex plate backward, it will get damaged. Alternatively, an interference in the balanced engine or a torque converter could cause serious damage to the engine and the expo tranny. Moreover, a damaged starter eats away the teeth of the ring gear and damages the flex plate.

Flex Plate Installed Backwards

Should there be a gap between the flexplate and torque converter?

You should maintain a small gap between the flex plate and the torque converter. To be precise, a gap of ⅛ of an inch is good. If there is no gap and they lie flat against each other, you have installed the flex plate backward.

How do I know if my flex plate is bent?

An idle engine will make chirping, clunking, and grinding noises. Moreover, you will hear whining noises from the starter and a knocking sound whenever you shift gears while driving. You will encounter a rough engine and loss of power at high speeds.

How do you mount a flex plate?

The flex plate is mounted on the engine crankshaft and the torque converter of your car’s transmission system through bolts. It works when the engine starts; it turns the flex plate, which turns the torque converter that pumps the hydraulic pump to provide power in the transmission system.

Wrap Up

A flex plate is better replaced than repaired as it is not expensive. Installing a flex plate is difficult, and you can easily go wrong. If you do not install the flex plate properly, it can lead to various problems. Thus, it’s better to leave it to the experts unless you are used to doing such jobs. Thank you for reading.

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Sean Mendez

Hi, I am Sean, a self-confessed petrolhead. I live in Boise, Idaho with a busy family of four and our energetic Labrador retriever. Thank you for visiting my website. You can find my email on the contact page.

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