So this is a Corolla 2005 model, with an automatic transmission. I am just curious about how my car works.

If I increase my RPM when I am in 1st gear, to say about 3k (by aggressively pressing down on the gas pedal), when I let go of gas pedal, it drops to 2k.

However, when I do the same at 2.3k RPM, and I let go of the gas pedal, it also drops to around 2k. I assume in both scenarios I am changing gears from 1st to 2nd, but why is the RPM change so much more in the first scenario?


1 Answer 1


This sounds like normal operation to me. As the car speeds up and you release the gas pedal, the transmission shifts to the correct gear. This may be 2nd or I may be 3rd or it may be whatever gear the transmission thinks it needs to be in for the engine power being applied and the speed of the vehicle. If you are going 35 MPH when you are doing either operation, it will drop the RPM down to the same level, because it's going into the same gear in both instances at the same speed. The control unit will decide where it needs to go, but remember, 2000 RPM is in the normal operating range for many vehicles, so this is approximately where it will settle when you let off the gas to allow it to shift.

To clarify something ... the drivetrain is made so if you are requiring the car to go quicker (pressing the accelerator pedal harder), the transmission will hold the gear until it reaches a fail safe shift point (a point at which is predetermined if you go over "this point" it will cause damage to your drivetrain -- this is on most stock production vehicles) or until you ease off the accelerator pedal, which tells the powertrain you no longer need to try and go quicker. Either way it will shift and bring the RPMs down, allowing for the best mix of fuel economy and need for the vehicle.

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