What’s That Noise? 8 Common Causes of Transmission Whining And How To Fix Like A Pro Mechanic

A properly functioning transmission makes no noise or might make the slightest momentary soft hum when you start on an incline. Otherwise, it should be completely silent. So, when your transmission starts to whine or makes a loud hum that persists in cadence when you accelerate, then you hear a sure sign of transmission in distress.

Sometimes, transmission whine is caused by a transmission fluid problem or perhaps excess wear and tear on the gears. Troubleshooting what’s causing the whine and what might need to be done to fix it starts with identifying the conditions causing it.

Situations That Cause Transmission Whine?

Some cases of transmission whine only occur under specific conditions. Taking the time to notice when the whine is loudest or when it seems to fade away might help you dial in exactly where the problem lies.

1. Transmission Whines in First Gear

If your transmission whines the loudest in first gear, it could be that the gear teeth are wearing out. The first gear is the most commonly used gear, and it tends to experience the most stress transferring torque to get the wheels moving.

If your transmission whines loudest in first gear and still whines as it makes its way up the tree of gears, it might simply be that you have low transmission fluid or bad transmission fluid.

2. Transmission Whines When Changing Down or Decelerating

If the transmission whine gets louder when you change gears or step on the brakes, it could indicate a torque converter problem. This often means that the pump within the torque converter is no longer functioning as intended. 

3. Transmission Whines in Park and Neutral but Not in Gear

If your transmission is whining when it’s not in gear, then it might be a sign that the needle bearings inside the torque converter are starting to fail. This usually happens simultaneously as the transmission struggles to shift gears. Especially as it reaches higher gears where needle bearings tend to take the most load.

A bad transmission oil pump can also make a whining noise when the car is in park or neutral. This is the pump motor itself failing, and you’ll often notice the transmission is running hot, getting stuck in gear, or refusing to go into gear. This can often happen in tandem with a clogged transmission filter that stresses the electric motor inside the transmission fluid pump.

4. Transmission Whines When Shifting Gears

Transmission whine when shifting gears can often be attributed to low or degraded transmission fluid. The transmission is not getting the lubrication it needs to make a smooth gear change, which is causing excessive stress on the gear teeth.

If you check the transmission fluid, it might look dark or low on the dipstick. If this problem has happened for a while, you might also notice tiny metal flecks in the transmission fluid from the grinding gears.

What Causes a Transmission Whining Noise?

Excess wear and tear on the gear teeth, low transmission fluid, and bad transmission fluid are three of the top most likely things causing your transmission to whine. However, there are undoubtedly other serious faults, like bad needle bearings in the torque converter, which could cause a whining noise, even when the car is sitting still.

1. Low Transmission Fluid with a Leak

Low transmission fluid is arguably the most common cause of transmission whine. Transmission fluid is technically an oil and plays a critical role in lubricating the gears, as well as working with pressure changes from the solenoids to engage clutch packs and bands.

When it’s low, there’s increased friction between the gears, which can cause whining and grinding. Low transmission fluid can also affect the input and output bearings and the torque converter’s needle bearings. Anyone or all of these can also contribute to a whining sound when in gear or even when parked.

How to Fix Low Transmission Fluid

On the face of it, it’s easy to conclude that all you need to do is pour some transmission fluid into the filler hole and go about your day. This might even make the transmission whine go away for a while.

Unfortunately, transmissions are sealed systems that don’t burn or use up the fluid inside. So, for your fluid to be low, there must be a leak somewhere. Until you fix that transmission fluid leak, you’ll end up with low fluid and a whining transmission again.

Sometimes, finding a transmission leak is easy, and sometimes, it can leave you feeling like you’re chasing gremlins. Adding a small amount of transmission fluid while the transmission is still warm will usually exacerbate the leak, making it easier to find.

The most common places to look for a transmission leak are:

Unfortunately, most of these leaks require a transmission specialist to repair them. The prices can vary from as little as $150 for something like a bad oil pan gasket to $ 2,000 for a cracked housing.

2. Bad or Degraded Transmission Fluid

Time and heat can cause the lubricating properties of transmission fluid to break down, manifesting as an increasing whine in the transmission. Essentially, the gears apply stress to each other rather than moving smoothly from tooth to tooth. The whining will often be louder in first gear, reverse, and during gear changes when the stress on the teeth is the highest.

If you look at the transmission on the dipstick, it should be pink and semi-translucent. If the fluid looks brown or dark or has particulate matter suspended in it, then it’s bad, and you need a complete transmission flush and fill. To say the least.

The real concern here is how the transmission fluid degraded in the first place. If it’s just that you haven’t changed the fluid in the last 30,000 to 50,000 miles, then it could have broken down on its own.

Otherwise, a problem with transmission overheating, heavy towing, or other faults in the system caused the fluid to degrade prematurely. In a scenario like this, you’ll need to figure out what caused the fluid to break down before it’s time and correct it as soon as possible.

How to Fix Bad or Degraded Transmission Fluid

If you catch it early, transmission whine caused by bad fluid might be easily fixed with a complete flush and fill. However, this usually requires replacing the filter.

The cost to have your transmission flush and fill will run from $75 to $100.

You’ll likely also need to replace the transmission filter, which could add another $75 to $100 for a final cost of $150 to $200.

Though the larger concern here is the potential for damage caused to other transmission components by driving on degraded transmission fluid, don’t be surprised if the shop that handles the flush and fills tells you that there are metal flecks in the fluid.

This means the poorly lubricated gears were grinding. If you start to notice other problems like grinding noises, slow gear changes, and slipping gears, you might need to have the transmission partially rebuilt by a certified transmission specialist

3. A Bad Transmission Oil Pump

As a transmission oil pump starts to fail, the electric motor often makes a whining noise. Since the pump plays a critical role in circulating transmission fluid for doing things like shifting gears and cooling the transmission, you’ll likely notice all kinds of other problems.

When a transmission oil pump starts to fail, the whining noise will still occur, even when the transmission is in park or neutral. You’ll likely also notice hesitating gear changes, the transmission getting stuck in gear, or simply refusing to engage first gear.

At the same time, the lack of transmission fluid circulating to the radiator and back makes it very hard for the transmission to dissipate heat. This compounds the problem by causing the fluid’s lubricating properties to degrade along with other transmission overheating issues.

How to Fix a Bad Transmission Oil Pump

When a bad transmission oil pump causes a whining noise, it must be replaced immediately to prevent more serious internal damage. Though usually, by the time you hear the whine, it’s a good bet that other components have been compromised.

The other problem is that a transmission oil pump replacement requires a transmission specialist to open the transmission housing. This laborious task will easily tack on an extra $350 to $500 to get to the bad transmission pump itself.

If it is just the pump, you can expect a part cost of around $275 to $450.

With labor, the final cost will be around $600 to $950.

Since you’re already opening up the transmission, the mechanic will rightly recommend giving the transmission a tune-up and/or partially rebuilding it. While this will hurt your bank account, it really is the wisest move.

The cost of a partial transmission rebuild can vary wildly. However, you can expect it to add at least another $500 to $750 to the final repair bill.

4. A Clogged Transmission Filter

A dirty, old, or clogged transmission filter might not allow enough pressurized fluid into the system, mimicking the whining noise you get from the low transmission fluid. Most transmissions rely on at least 50 to 75 PSI of pressure to properly circulate the transmission fluid and fully lubricate all the moving parts. When a clogged transmission filter prevents the smooth flow of fluid, it can cause whining, grinding, overheating, and other transmission performance issues.

This might manifest as the transmission is slow to shift into first gear, then suddenly dropping out of gear when the filter can’t pick up enough fluid to maintain sufficient pressure in the valve body. You’ll likely also notice grinding in the gears from poor lubrication and the persistent whining noise that climbs up with the gears.

How to Fix a Clogged Transmission Filter

It would be best to have your transmission filter replaced every 30,000 to 50,000 miles. However, some manufacturers recommend doing it every two to three years. This might also call for replacing the transmission fluid and possibly the transmission gasket.

You can usually replace your transmission filter at most shops that offer oil changes. However, if you need a total gasket replacement as well, or you’ve seen signs of other problems like metal shavings in the transmission fluid from the poorly lubricated gears grinding, then a transmission specialist will be needed.

The cost to have your transmission filter replaced is usually less than $100.

If you also need to replace the gasket, it will add another $75 to $100 to the final repair bill.

It’s also a good idea to have a transmission flush and fill while you’re at it, which could add yet another $75 to $125 to a final repair bill of $250 to $350.

5. A Bad Input or Output Shaft Bearing

If there’s a problem with the transmission input or output shaft bearing, it will also cause a whining noise. The input shaft comes directly from the engine and will spin even when the car isn’t in gear. A bad input shaft bearing can whine when the car is in park or neutral.

If it’s a bad output bearing, the car will whine when you put it in gear and start moving. You’ll likely notice it most in first gear, but the transmission will whine as you accelerate.

How to Fix a Bad Transmission Input or Output Bearing

Unfortunately, when an output or input shaft bearing goes bad, it takes a transmission specialist to open the housing.

Right away, this adds at least $350 to $500 in labor costs alone.

The cost for the actual bearing itself is usually less than $50. So, if it’s just the input bearing, you’re looking at a final repair bill cost of $400 to $600.

If a bad output bearing is causing the transmission to whine, you’re looking at a similar cost. However, there’s a risk of damage to the drive shaft or the U-joints. While these repairs don’t have any appreciable impact on the transmission whine problem, they can add hundreds of dollars to the final repair bill.

6. A Bad Throw-Out Bearing in a Manual Transmission

A bad throw-out bearing in a manual transmission will also cause a whining noise when you engage the clutch. It often starts out as a small squeak and gets louder and louder the more you use the clutch. You’ll likely also notice the clutch pedal vibrating strangely, and you’ll have an increasingly tough time getting the manual transmission to change gears.

As the failing throw-out bearing gets worse, you’ll notice the clutch pedal feeling increasingly stiff. Then, right as the clutch is about to fail, the pedal will seem to fade to the floor. At this point, you’re in serious trouble, as the throw-out bearing is essential in helping the clutch when you change gears. So, if you procrastinate this type of transmission whine, you will inevitably get stuck on the side of the road in neutral.

How to Fix a Bad Throw-Out Bearing

If your manual transmission whines when you engage the clutch due to a bad throw-out bearing, you want to catch it as soon as possible. If you see it in time, you might get away with just having the bearing replaced. If you procrastinate too long, you’ll need to replace the clutch and perhaps some other linkage components!

If you’re an accomplished DIY mechanic, you might be able to replace your own throw-out bearing. Though this is a five-star knuckle buster repair that will have you contorting your body in uncomfortable gymnastics poses while trying to work with tools in hard-to-reach places. It will also eat an entire Saturday, if not your whole weekend!

So, even if it’s within your depth of skill, you might still want to take it to a mechanic.

A Comprehensive Video on Replacing a Clutch and Throw-Out Bearing

The part cost for a throw-out bearing will run you around $85 to $190.

The labor cost to have a mechanic replace the throw-out bearing and install a new clutch can run from $750 to $900.

7. A Bad Planetary Gear

A transmission whine with a persistent grinding, roaring, or humming noise could be a sign that your transmission’s planetary gear is failing. This is a major system fault that will cause the teeth from the sun gear, ring gear, and the three planetary gears to not meet up perfectly.

They’re found in most modern automatic transmissions and require proper lubrication. It’s possible that some part of the planetary gear system wore out on its own. Though chances are good, a problem with your transmission fluid accelerated the wear and tear, leading to a premature failure.

How to Fix a Bad Transmission Planetary Gear

An automatic transmission that whines and grinds due to a failing planetary gear will need a major overhaul. Depending on the state of the rest of the transmission, it might even be more cost effective to have the transmission completely replaced.

The part and labor cost to replace the bad planetary gear will run you at least $2,700 to $4,000, which is the same as completely replacing the transmission with a new one. Except with the new transmission, you get the peace of mind that no other gremlins are hiding in the system!

8. Bad Torque Converter Bearings

Bad bearings, like the needle thrust bearings inside a transmission’s torque converter, will often start out with a whining noise. The whining noise might linger in the background when you’re sitting in the park or neutral. Then be louder when you downshift or right as the transmission is about to change up a gear.

The longer you let bad torque converter bearings go, the more likely you are to suffer serious damage to other transmission components. So, catching it early is essential for keeping the repair or replacement cost low.

Dirty or contaminated transmission fluid is one of the most common causes of torque-bearing failure. If your transmission fluid looks dark, has metal flakes floating in it, or has dark sandy particles, there’s a good chance the fluid is the root cause of the torque-bearing failure.

Though solenoid problems, low transmission fluid, and leaky seals can also lead to an early demise of the torque converter.

How to Fix Bad Torque Bearings

When the bearings go out in a torque converter, it’s usually more cost-effective to replace the entire unit rather than shoulder the insane labor costs of overhauling the old one and replacing the bearings. Though one silver lining here is that the torque converter on most automatic transmissions is a self-contained unit. It can be replaced without the typically high labor costs of opening the transmission’s transfer case.

If you’re an accomplished DIY mechanic, you might be able to replace your torque converter yourself. However, this is a labor-intensive job. Installing the actual torque converter itself doesn’t take that long, but getting at it and getting it out is the majority of the job. So, you might want to take it to a transmission specialist.

A new torque converter’s parts range from $150 to $350.

When you add the labor cost to have a transmission specialist remove the old one and install a new one, you have to shoulder another $500 to $1,000 onto the final repair bill.

All told, you’re looking at a final cost of $650 to $1,300 to have the torque converter completely replaced.

How to Stop Transmission Whine

If you’re driving down the road and your transmission starts to whine, it’s most likely a problem with the transmission fluid or a leak that’s caused the fluid to drop. Pull over and give the fluid a quick check. If it’s low, look under the car right away. Most transmission fluid leaks are easier to spot when the transmission is warm and/or the car is running.

If you see a leak or the transmission fluid is low, you should add a small amount of fluid. Working in small doses and waiting for 2 to 3 minutes for the fresh fluid to pool will keep you from accidentally overfilling the transmission.

If the fluid is dark, or you see metallic flecks in it, and it’s not low, then you’ve got bad transmission fluid. The wise move here is to have the car towed to prevent more serious damage to the transmission.

How to Prevent Transmission Whining?

Preventing transmission whine starts with good old-fashioned routine maintenance. This starts with keeping tabs on your transmission fluid to ensure it isn’t low, degraded, or contaminated.

They also ensure a complete transmission flush and fill every 30,000 to 50,000 miles or when the manufacturer recommends it. This will include a transmission filter change, an inspection of the pan gasket, and other critical components.

If you do a lot of towing, staying within 80% or less of the rated weight capacity is also wise. This will reduce the risk of the transmission overheating causing degraded fluid that accelerates problems with other transmission components like the torque converter bearings. 

If your car has a manual transmission, you should also be mindful not to ride the clutch or make abusive gear changes. Reducing clutch stress will go a long way toward not prematurely wearing out the throw-out bearing.

Frequently Asked Questions

Is it normal for a manual transmission car to make a whining noise?

A properly functioning transmission shouldn’t make any noise while driving down the road. You might hear a slight whine at most when you first set up an incline or put it in reverse. This is often due to momentary stresses on the gear teeth or the fact that the reverse is spur gear.

Will Stop Leak Additives Fix a Transmission Leak?

The makers of transmission stop leak products might mean well, but their products can easily cause more harm than good. While it might temporarily plug up a failing seal, the stop leak can damage other seals in the transmission that are still good. It can also gum up bearings and other moving parts in the transmission, which will cost a lot more later on down the line.

Conclusion

Transmission fluid problems such as low, degraded, or contaminated fluid are often the route cause of transmission whine. Problems with transmission components like the torque converter bearings, input and output bearings, or planetary gear can usually be traced back to poor lubrication due to transmission fluid issues.

So, staying on top of your transmission fluid is always a good idea. Make sure to change it according to factory specs, and always watch for leaks or signs of bad transmission fluid. If you notice a problem, don’t wait for transmission whining noises before taking it in.

Suppose your car has a manual transmission; you must also be mindful not to ride the clutch or use it abusively through gear changes. You might have a throw-out bearing if you hear squeaking noises and whining that sounds like it’s coming from the clutch pedal or the firewall.