Your transmission is responsible for making your car move – it transfers the power from the engine to the wheels. During normal operations, you’ll definitely hear at least some noise. However, when it begins making unusual sounds, particularly a whining noise when in gear, it’s a sign that there is something wrong. The trouble may be pinpointing what it is.
How this system works:
Transmissions work in different ways, depending on whether you have a manual or an automatic transmission. If you have a manual transmission, then you’re responsible for changing the gears as your speed (and engine RPMs) increases. For instance, you’ll press the clutch pedal and shift into first gear, then into second gear, then third, and so on in order to accelerate. If you don’t shift gears but continue to accelerate, the transmission will begin to whine very loudly.
In an automatic transmission, all of this is done for you by the transmission and the car’s computer. All you have to do is put the gear selector in drive, and press the gas pedal. The transmission will automatically shift at certain engine RPMs to ensure a smooth acceleration process.
As you can imagine, both manual transmissions and automatic transmissions require many different components in order to operate. Some of these can create a whining noise when in gear. For some transmissions, a little whine in certain gears is completely normal. In others, not so much. The real thing you want to watch for here is a “new” whining noise. Of course, that can be difficult to determine if you’ve just purchased the car or haven’t owned it long enough to know what is normal and what’s abnormal.
Common reasons for this to happen:
Low Transmission Fluid: For both manual and automatic transmissions, the primary cause for whining when in gear is low transmission fluid. If the fluid is too low, then the internal components of the transmission are not lubricated properly. What you’re hearing is actually friction between those parts, and it can lead to significant damage. If the fluid is low, it’s advised to check for transmission fluid leaks.
Normal Operation: As mentioned, some transmissions have an inherent whine that is completely normal. Depending on the make and model, the whine might be primarily audible in first gear, or it could be more noticeable in third gear, or some other gear. The best defense here is to know what your transmission sounds like normally.
Worn Clutch and/or Flywheel: If you drive a manual transmission, there’s the possibility that your clutch is worn out and/or your flywheel needs to be resurfaced. When these components begin to wear, it’s possible to hear whining, grinding and other abnormal sounds.
Bad Throw Out Bearing: If you’re hearing the whine while the clutch is not engaged, there’s a chance that it’s the throw out bearing. However, it’s more common to hear noise from this bearing while operating the clutch, rather than driving in gear without any pressure on the clutch pedal.
Bad Input Shaft Bearing: This is an internal bearing within the housing of the transmission, and it can create a whining sound when it begins to fail.
Bad Wheel Bearing: Wheel bearings are located in each wheel hub, but the sound can travel and seem as though it’s coming from the transmission. It’s more usual for a failing wheel bearing to create a roaring sound, but it’s possible for them to create a whine while driving.
What to expect:
A certified mechanic will come to your home or office to inspect your transmission and verify the whining noise. The mechanic will then provide a detailed inspection report that includes the scope and cost of the necessary repairs.
How it's done:
The mechanic will first inspect the transmission, including the level of transmission fluid. However, it will be necessary to test drive the car to verify the sound and pinpoint its source. The mechanic will also inspect and troubleshoot other areas of the vehicle to eliminate other possibilities.
How important is this service?
If your transmission is whining while in gear, it could be normal, or it could be a sign of a deeper underlying problem. Your transmission is a critical part of your car and if it breaks down, you won’t be going anywhere. One of our professional mechanics can inspect your transmission, listen to the whine, and repair the problem.