Why Does My Car Make A Crunching Noise When I Change Gear?

By Julia Freeman

Gear changes should be smooth and silent, so any noise or vibration is evidence of something amiss. If your “crunch” sounds like metal teeth colliding with metal, you probably don’t need a mechanic to tell you it is doing no good. Gearboxes are expensive so you'll need to get to the bottom of it as soon as possible.

Car gear

Rule out the obvious

Intermittent noises can be driver error. Like all of us, at some time you discovered what happens when you engage a gear without using the clutch. If that is the noise you’re hearing, be sure to rule out obvious factors such as footwear. If you’ve swapped from platforms to sandals you’ve effectively made your leg shorter. Pushing the seat back has the same effect and can trick you into putting less pressure on the clutch pedal.
If the noise is more than intermittent, then the clutch itself must be investigated. Driving on city streets and sprinting from lights to lights can wear a clutch quickly. Regular car servicing by qualified fitters at a Protyre garage will help you to anticipate the life left in your clutch and gearbox and plan for remedial works safely in advance.

Clutch and fluid problems

Clutch problems are definitely a case of “a stitch in time saves nine”. You may only need a cable tightened or hydraulic fluid replaced. However, ignoring the problem will eventually damage both the clutch and gearbox. Most issues, such as a worn pressure plate, are easy to fix if caught early.
Check your car service schedule to see when the transmission fluid was changed. Fluid can last for 200,000 miles in some vehicles but as little as 15,000 in others, consequently it is often overlooked. Tired fluid is an underlying cause in a high percentage of gearbox breakdowns. You can book yourself in for a service check using our online contact form.

Synchronisers and bearings

Crunching between certain gears and not others, or when accelerating sharply or cornering, suggests a problem with the synchroniser blocker rings that guide the cogs together. The problem often starts in second gear then spreads upward. Again, catching the issue early is important.
If the sound happens when you put your foot down but before you move the gear stick, the problem could be the release bearing. If the sound happens just as you release the clutch and move off, it could be the pilot bearing. Both require a complete clutch replacement, but early attention can save the gearbox.

Other causes

Noises when changing gear aren’t always caused by the gearbox. Suspension and steering issues can interact with changes in torque and acceleration. Consider this possibility if you also notice pull on the steering wheel or uneven tyre wear.
Most Protyre garages will fit you in for a free tyre inspection and alignment check at short notice and have a full range of quality tyre brands including Bridgestone and Pirelli available at all times.
In the end, every part of a car is connected to every other, and it is better to maintain it altogether than to chase each fault one at a time. Regular car servicing is always a good investment.

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About the author

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By Julia Freeman
Julia is Head of Brand Marketing for Micheldever Group and loves engaging with customers and the business as a whole to deliver their automotive needs.
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