The transmission in an automatic car has plenty of moving parts and is continuously shifting gears. Despite that, it’s designed never to make noise or cause the vehicle to shake. So when the car jerks because of the transmission, that’s a problem requiring your attention.
Your automatic transmission car is jerking because of a problem with the transmission fluid. Too much or too little fluid can cause the jerking, as would transmission fluid that’s too dirty. Besides that, a dirty fluid filter or a leak could cause the fluid pressure to drop too low. Some cars will stop jerking once they warm up because the transmission fluid was too cold to work correctly.
Jerking in an automatic transmission car can be terrifying if you don’t understand why it’s happening. But don’t worry, as this guide will clear up everything for you. You’ll discover why your car is jerking that way and what solutions you can use to resolve the matter.
Why Is My Automatic Transmission Car Jerking?
An automatic transmission car should only experience gentle vibrations and humming under normal circumstances. Jerking, however, is not normal and indicates a significant problem with the transmission system.
Here are the reasons why your automatic transmission is causing the vehicle to jerk and what you can do to fix the problem:
1. Too Little Or Too Much Transmission Fluid
Automatic transmission fluid, or ATF, is the lifeblood of your car’s transmission system. Not only does it keep the moving components lubricated and prevent overheating, but ATF is a hydraulic fluid that gives the system its power.
So, your car is most likely jerking due to a lack of transmission fluid. Without enough fluid, the system struggles to transfer power to where it’s needed. That will then prevent the gears from engaging and disengaging firmly, causing the vehicle to jerk while attempting to do so.
Unfortunately, the same can also happen if there is too much ATF in the system as well. An excess of fluid will lead to foaming, and that will cause a drop in fluid pressure. That lack of pressure will also prevent the gears from shifting firmly, leading to the same jerking sensation.
How to fix it: Thankfully, this common problem has a straightforward solution. Firstly, you must top off the ATF until there’s enough of it in the system. Then, if there’s too much of it, you must drain the excess until the optimal fluid level is achieved.
2. Fluid Pressure Is Too Low
As you read above, a lack of fluid pressure can also cause jerking in the transmission, which is felt throughout the vehicle. However, a shortage or surplus of ATF isn’t the only reason that low-pressure conditions can occur.
Instead, there’s probably a leak somewhere in the transmission system. The transmission fluid pressure will drop when the system is compromised by a leak. As a result, the fluid can’t flow through the valves correctly to engage the gears as needed.
Transmission leaks typically happen in the fluid hoses and their connections. Hoses can often develop tiny holes that are challenging to notice from afar. Meanwhile, the clamps securing the connections could also come loose due to vibrations from the engine.
How to fix it: Firstly, you must inspect your automatic transmission, particularly its hoses and hose connections. Doing so will help you identify the source of any leaks.
Depending on the problem, you might have to replace any leaking hoses and reattach them securely.
After completing this repair, you must replace any lost transmission fluid due to the leak.
3. Dirty Transmission Fluid
Believe it or not, an automatic transmission car can still jerk despite having the correct amount of ATF in the system. That’s because the fluid is likely dirty from excess wear after being used for too long.
Typically, you must replace ATF with fresh fluids every 30,000-60,000 miles, depending on the quality of the fluid. The longer you delay the replacement, the dirtier the fluid will naturally become.
Automatic transmission fluid will lose its qualities the dirtier it becomes. So, it will fail to flow through the valve body, causing the transmission to struggle when shifting gears.
As a result, the transmission will experience jerking, which you can feel while sitting in the vehicle’s cabin.
How to fix it: The only solution for dirty transmission fluid is to drain everything and replace it with fresh, high-quality ATF.
Depending on how long that fluid has been circulating in the transmission system, flushing it out is also an excellent idea. That way, you can ensure that any build-ups of debris or other impurities will also be removed.
4. Clogged Transmission Filter
Wherever there’s fluid, there’s a filter. That applies to any major car component like the engine, and most definitely to the automatic transmission system as well.
The filter’s purpose is straightforward: it removes all impurities from the ATF and prevents them from circulating. However, that filter will eventually become saturated over an extended period.
When that happens, the saturated filter will restrict fluid flow and cause the pressure to drop.
As you saw earlier, pressure drops and a lack of flowing ATF will cause the system to struggle when shifting gears. That will lead to the jerking that your vehicle experiences while driving.
How to fix it: Firstly, you must remove and inspect the transmission filter. In most cases, you can restore the filter by cleaning it thoroughly.
However, filters that are excessively clogged and damaged must be replaced with new ones. Doing so will quickly restore your transmission’s performance and stop the jerking from happening again.
5. Extremely Low Temperatures
Last but not least, you should also consider the climate and surrounding temperatures. Automatic transmission car jerking can still happen even if the transmission system is in perfect condition. But if the ATF is too cold, it won’t flow smoothly and cause the transmission to jerk as it struggles to shift gears.
This problem typically happens in the first few moments when you start your vehicle. However, the jerking gradually fades away as you continue driving and your vehicle reaches optimal operating temperatures.
How to fix it: Suppose your automatic transmission car is jerking because the ATF and the transmission are far too cold. In that case, you only need to give the vehicle sufficient time to warm up before you begin driving.
Start the engine and let it run for a few minutes or until the cold engine indicator on the dashboard turns off. By that time, the warm ATF will circulate throughout the transmission, lubricating its components and helping everything function correctly.
You can also start your drive slowly, maintaining a low speed for the first 10 miles. That way, you’re minimizing the demand on your automatic transmission as it continues to warm up to optimal temperatures.
When functioning correctly, jerking should never happen in an automatic transmission vehicle. When the transmission malfunctions, the jerking it causes can be felt throughout the entire vehicle.
An automatic transmission jerks because there’s something wrong with its automatic transmission fluid, or ATF. Too little or too much fluid and ATF that’s gone dirty can all prevent the transmission from switching gears smoothly and cause jerking. Plus, the filter could be dirty, or there might be a leak causing a pressure drop. When everything is in good condition, excessively low temperatures can also affect the ATF and cause jerking.