The term "neutral transmission" refers to the state when the transmission is shifted into the neutral position or neutral gear on the gearbox. Many people believe that putting your car into neutral when you're traveling downhill will help to save fuel and in turn save money.
The purpose of the neutral position is to allow your vehicle to run while standing still without requiring the driver's foot to be on the break. In older model vehicles, this may have made a difference, but now it is just as easy to shift the vehicle into park.
Depending on the type of vehicle being driven, neutral gear may or may not be harmless to the engine. Since automatic transmissions automatically shift gears depending upon the amount of pressure built on the transmission fluid, such vehicles will automatically switch into a neutral-like state when coasting downhill. Manual, or standard, transmissions do not require being shifted into neutral to coast downhill, but doing so may help to preserve your engine.
To see how a transmission in neutral position works, you need to understand the basics of how a transmission works. Several different shafts make up the transmission, transferring motion from the engine and matching the rounds per minutes produced by the engine. These columns connect to a separate shaft that is geared to rotate at the same rate as the wheels on the vehicle. The shafts turning with the engine and the shaft turning with the wheels meet to determine which gear is needed to make the engine RPM and the wheel RPM work together successfully. The shaft connected to the wheels is built so that it still turns when the vehicle is coasting, allowing the vehicle to continue running without being powered by fuel.
Many people advise that you shouldn't use neutral gear when driving. They insist that with your engine disengaged, you lose control over the vehicle's speed and must rely solely on the brakes. Aside from the possibility of an accident, many believe that using neutral to coast downhill results in a more frequent need for new brakes and brake pads. Many insist that the fuel saved traveling in neutral downhill is not much of a monetary gain at all, and is not at all worth risking your engine or yourself.
Putting your car into neutral is especially helpful in situations when you've run out of gas or for whatever other reason you need to push the car forward or backward. If you still insist on saving a few pennies, use neutral gear safely when traveling on a level surface or a very small downgrade.
