Why is there a grinding sound when I shift into reverse gear? | AutoGuru
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Why is there a grinding sound when I shift into reverse gear?

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Updated 10 Dec 2019

Fionna Blackburne

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If you are grinding reverse gears it means the gearbox (also known as a transmission) has not fully disengaged from the engine and the gears are still rotating.

One trick to eliminate the problem is to momentarily shift into a forward gear before quickly shifting into reverse.

If this doesn't work, it is likely you have a problem with the clutch or gearbox and it’s time to get your car to your mechanic for professional advice.

What does the transmission do?

“Get your motor runnin', head out on the highway” . . . The gearbox is essentially what allows you to control how fast or slow you want to run your car on that highway.

The lower the gear, the slower the wheels turn in relation to the engine speed.

There are four types of car transmissions:

The Manual Transmission

Probably the most straightforward and oldest type of transmission still in use.

This gearbox uses a friction clutch inflected by the driver’s foot to connect the engine’s rotational energy to the transmission’s input shaft.

A fixed set of gears are engaged using a synchro and gear-selector fork connected to the gear stick operated by the driver’s hand.

This type of transmission is arguably the easiest and cheapest to repair.

The Automatic Transmission

By far the most common transmission on the road today.

It uses a complex torque converter to transmit the engine’s rotational energy, while gear shifts are controlled by the vehicle’s computer and accomplished with a planetary gear set and a series of clutches and brakes.

All you, the driver, have to do is select a gear on the gear selector.

This transmission is mechanically complex, which makes it more prone to failure and more expensive to repair.

Continuously variable transmission (CVT)

The CVT is similar to an automatic but operates using a completely different mechanism.

The CVT doesn’t have gears, instead, it uses a system of belts and pulleys to produce an enormous range of ratios.

The computer in the car decides how to adjust the pulleys to create the optimal ratio for the particular driving situation.

CVT’s are not as complicated as an automatic transmission.

They are, therefore, less prone to fail and are not as expensive to repair as an automatic.

Semi-automatic and dual-clutch transmissions

Essentially a hybrid between a fully automatic and manual transmission.

These gearboxes are mainly found on race cars and expensive sports cars.

This gearbox is so complex that it needs frequent and costly repairs.

If you’re unsure of what’s going on, the easiest way to find out is to book in with a mechanic through AutoGuru.

When we say easiest, we mean the easiest!

You could be all booked in within a few clicks, and back on the road with a happy gearbox.

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Written By

Fionna Blackburne

Fionna is the owner of Southeast Auto Mechanical in Beenleigh, Queensland. A former lawyer, Fionna decided on a radical career change, qualified as a light vehicle mechanic and took over Southeast Auto in 2016.

As well as delivering quality service to their customers, Fionna and her team run an award-winning, free car maintenance workshop program for women.