automatic transmission high rpm before shifting

Automatic Transmission High RPM Before Shifting – Problem Diagnosed

The transmission in your car is responsible for delivering power from the engine to the wheels. So, for the effective performance of your car, it is necessary that your transmission is in good working condition. However, you can face the problem of automatic transmission high rpm before shifting in your car. If it occurs once, then it’s not an issue, but if it occurs several times, then it is a serious problem.

The issue of the automatic transmission’s high rpm before shifting should be resolved quickly, as the severe damage will be expensive.

In the following blog, we will understand

  • What are the consequences of the AMT high RPM before shifting?
  • What are the causes, and how to fix them?

Effects of Automatic Transmission High Rpm Before Shifting

Car revs high while driving automatically and doesn’t accelerate as per the expectations, then you might be facing the issue of the transmission slipping.

Due to the transmission revving high, your engine will use more fuel. Moreover, there will be more wearing and tearing. It will be unsafe, too, if you lose control of the brake pedal. Because of the erratic shifting automatic transmission, you will feel delayed accelerations and will have lesser control over the car.

Reasons for Car Revving High While Driving Automatic


If your car won’t move until high rpm, then the transmission is at risk. When the transmission is not functioning well, it causes delayed shifting when accelerating. There are multiple reasons for automatic transmission’s high rpm before shifting.

Non-Synchronization of Transmission

If there is a misalignment in your transmission, the gears may slip, and the engine may rev rapidly. Because the gears won’t properly engage, that will happen. And the camshaft or timing belt that is worn out is mainly responsible for this.

High RPMs can be caused by out-of-sync gears. You can have engine issues like knocking if it is not corrected. Your engine’s valves can potentially sustain damage.

Way to Rectify

The best way to fix it is to replace the timing belt or camshaft. You can also adjust the timing of your transmission by a professional, but it is a more expensive option.

After the replacement, drain the old fluid out and replace it with fresh fluid. Apply lubricant to maintain the gears in sync.

Wearing of Solenoid

Fluid flow into and out of the transmission is regulated by solenoids. So, if they aren’t functioning properly, the car over-revs when changing gears automatically, and the gears may slip.

If the solenoid is wearing down, it may affect the functioning of transmission. Having a dead battery will also affect the power generation from the solenoid.

Way to Rectify

Test the battery first if you are experiencing solenoid problems. A voltmeter is helpful in assessing it.

Another relatively easier method to fix it is changing the solenoids. You can change worn-out solenoids without having to dismantle the valve body.

Defective Speed Sensor

Another cause of car shifting weirdly is speed sensors. Speed sensors relay signals to automatic transmissions and tells them when to shift gears.

If the speed sensor is unable to detect your car’s speed with sufficient accuracy, your vehicle may fail to shift gears appropriately. Consequently, it causes the engine to put more effort.


Firstly, you should inspect the wiring underneath the car and replace the wiring in case of damage. If the wiring is fine, then it is the speed sensor at fault. Replace the speed sensors to fix the problem of the car not changing gears while revving high.

Leaking Transmission Fluid

The transmission fluid provides lubrication to the transmission. It ensures that the temperature of transmission is at an optimum level. So, when there is leakage or low transmission fluid, then the transmission will not receive enough lubrication. It will cause transmission slippage. All of it will result in higher RPMs. If there is excess loss of fluid, there will be a high-temperature rise, causing a fire.


The obvious way to resolve automatic transmission high rpm before shifting issue is to prevent leakage. Apply sealant to stop the transmission fluid leakage. Check your seals, gaskets, or O-rings. Replace the worn-out ones.

Slipping Clutch

Due to a defective clutch, the car rpm increases suddenly. When the slipping clutch is worn out, the amount of pressure required to engage a clutch will gradually decrease. So it will begin to slip. A defective clutch will not be able to transfer power from the engine to the transmission. It will ultimately cause transmission failure.


The best thing to do if your clutch is worn out and slipping is to replace it. It will be a costly affair, but it will prevent you from transmission failure. If you want to save money, you can replace it with used automatic transmission. However, changing a clutch yourself is not a simple task. It’s preferable to leave it to a mechanic.

Frequently Asked Questions

What RPM is the ideal one for an automatic transmission to shift?

Transmission shifts at 3000 rpm for up and down at 1,000 RPMs work best. However, it varies from vehicle to vehicle.

Can low transmission fluid cause high RPMs?

Low transmission fluid causes slippage causing higher RPMs. It can make your transmission malfunction.

Can a vacuum hose be responsible for high rpm before shifting in an automatic transmission?

The vacuum hose that transports air from the engine to the transmission malfunctions. The engine may rev up to a high rate if one of these hoses is leaking.

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Author Details
Automobile Engineer , Spare Part Zone

I am an automobile engineer with more than ten years of experience in the field. I like giving my readers accurate information and ensuring that they acquire the best components for their vehicles.

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