You may have seen signs along the roadway saying, “No Jake Brake” or “No Engine Braking” and wonder what they mean. It seems like an odd term and you are probably trying to figure it out right now, even while you are reading this. Well, if you have ever heard a big rig making an extra loud sound while slowing down, you have experienced the sound of engine braking. In technical terms, it is called downshifting as that is what it is the driver is doing. So, what is it?
Engine braking, or downshifting, occurs when a driver uses the engine to slow the vehicle down instead of simply applying their brakes. Although the term can be applied to the action being used in your family car as well, it is more commonly used on large, heavy vehicles including busses and semi-trucks.
Semi-trucks use a Jake Brake (nicknamed after the brake’s manufacturer, Jacob’s Vehicle Systems), which, at the push of a button, can shut off fuel to a certain number of cylinders. This decreases power to the wheels and reduces the truck’s speed.
Can I shift my car into a lower gear while driving without damaging it?
There are some technicians who will say that this is completely harmless for your car when slowing the vehicle when declining a steep grade and that you won’t do any harm. Others say that it is bad for your car and you should just slow down using your braking system.
Either way, something is going to wear down, you just must decide what part that is on your vehicle, the braking system, or your transmissions. The increased friction of riding your brakes down a hill can wear out your brake pads. But the increased friction of downshifting can wear out your clutch or transmission sooner. With both scenarios, something is going to wear down and whichever system you choose, the repair could be expensive.
In general, engine braking is not bad for your car. In fact, it does offer many benefits. Drivers have more control while slowing down, reducing the danger of jack-knifing that comes along with using mechanical brakes. Engine braking can also increase the life of your brakes by preventing them from overheating on steep downgrades. In some large trucks, it can break up excessive carbon build-up inside the exhaust system enabling it to operate more efficiently.
So, will engine braking result in damage to my car?
When done incorrectly, downshifting on a steep grade can damage your vehicle’s driveline components. Is this more harmful than riding your brakes down the hill? No, but you need to be as smooth as possible when doing it. Here’s how:
Let off the throttle as you reach the top of a hill. Then, downshift one gear. Although you may not feel anything different with your vehicle, you will have properly downshifted, or engine braked. You may even have to downshift into another gear to feel the engine braking.
If you choose to use your braking system instead, you can but this information is useful is your brakes fail on a decline and engine braking is the only option. For more information, consult your owner’s manual for any specific recommendations for your vehicle.