Is it OK to shift a Car into Drive While Rolling Backwards?


Will this Habit Hurt Your Vehicle’s Transmission?

We’re all in a hurry and we all do things that might not be the best for our car; but will it be a real issue for the life of your vehicle? It all depends on the bad habit, but a big debate is on shifting your vehicle from reverse to drive while still moving backwards. Will this hurt your car over time or is it an old wives tale? We debate it below.

How Does An Automatic Transmission Shift?

First we must give you a crash course on how a typical automatic transmission works when you push on the throttle or shift gears. Most automatic transmissions are a fluid drive type transmission where the transmission and the engine are connect via a torque converter that automatic transmission fluid flows through and acts as your connection to drive the wheels in the vehicle. When driving the fluid pressure will build up and help shift gears and smoothly apply the power to the wheels. Automatic transmissions are built to give you smooth, consistent power to the wheels without feeling the abrupt acceleration or shifting of gears.

For this reason there is some play or “slop” figured into an automatic transmission and torque converter. The fluid pressure in the torque converter needs to rise enough to lock up the converter and drive the wheels so sometimes there is a momentary delay when you accelerate from a stop or even a slight rolling back of the car when pulling out on a hill. For this reason when slowly (the key word is SLOWLY) backing up the pressure inside the torque converter usually isn’t high enough to complete the connection between the transmission, the engine, and the wheels and the split second when you shift from reverse to drive the transmission isn’t being shocked because the torque converter is essentially “free wheeling” and it takes up the change in direction.

Once you give the car some throttle to pull forward the pressure in the transmission and torque converter rise and the converter sends the engines power through the transmission and to the wheels. This doesn’t mean you can “floor it” in reverse and slam the car into drive… this shock certainly WILL cause damage! As a rule of thumb you should always come to a FULL stop before changing your vehicles direction or going into park. Over time you could be going just a little too fast and shock the transmission which could cause compounding damage over time. But if you do it occasionally at very low speeds (under 2-3MPH) you won’t be doing any real damage to the transmission itself (even though it isn’t the best practice.

If you need to service your transmission or make replacement brake, fuel, or transmission lines Eastwood has you covered. See all of our Auto Specialty Tools HERE.

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