Will Low Transmission Fluid Cause Damage?

The transmission in your car is critical to allowing your car to move forward and backward as well as allowing you to shift between gears.  That’s why it’s important that the transmission fluid inside the transmission is replaced from time to time and doesn’t get too low.  Can low transmission fluid cause damage to the transmission over time? What can happen if your transmission fluid isn’t replaced?

So will low transmission fluid cause damage?  Yes, low transmission fluid can cause damage to the transmission if the fluid levels in the transmission are low for an extended period.  Since transmission fluid is critical for keeping the internals of the transmission lubricated and allowing automatic transmissions to shift having low transmission fluid can cause damage to the transmission if left that way long enough.

But what are the symptoms of low transmission fluid?  How do you tell if your transmission fluid is low?  Keep reading to find out.

Can Low Transmission Fluid Cause Damage to the Transmission?

Having low transmission fluid can cause your transmission to hesitate when shifting gears and can cause the gears within the transmission to grind against each other without proper lubrication.  If the gears within the transmission aren’t lubricated this can cause metal on metal contact and can greatly reduce the life of the gears within the transmission.

What Is The Purpose of Transmission Fluid?

The main purpose of transmission fluid is to lubricate the moving parts inside of your transmission.  Automatic transmissions also use transmission fluid to instruct the transmission on when to shift gears.  With manual transmissions transmission fluid is just used to lubricate the gears inside of the transmission.

What Are the Symptoms of Low Transmission Fluid?

1. Slipping When Changing Gears

Since automatic transmissions rely on transmission fluid to shift gears you may notice hesitation or slipping when your transmission is changing gears.  When a transmission is slipping when changing gears you will notice that your tachometer or RPMs will raise in between shifting gears when really your RPMs should drop as you shift gears.

Your car will also hesitate and not want to put the power from the engine to the ground when your transmission is low on transmission fluid.

2. Check Engine Or Warning Light

On most modern cars they will have sensors inside of the transmission that will alert you when the transmission fluid levels get too low.  The alert may come in the form of a check engine light or another warning light letting you know that your transmission fluid levels are low.

If you have a check engine light or warning light on the dash but your car isn’t telling you what is wrong you can use an OBD2 scanner tool to scan your car to determine what is causing the warning light.

3. Dark Brown or Dark Red Fluid

Another indicator that you are low on transmission fluid is that the transmission fluid is dark brown or dark red.  Transmission fluid should be bright red and should be clear when inspecting it. It could be that your transmission fluid is old but it’s best to check your transmission fluid levels if you notice that your transmission fluid is dark brown or dark red in color.

4. Burning Smells

Burning smells coming from your engine bay or underneath the car can also indicate low transmission fluid levels.  Transmission fluid is mainly responsible for lubricating the moving parts within your transmission but it also plays a role in making sure that your transmission doesn’t overheat.  If you notice burning smells it’s a good idea to turn off your engine and check your fluid levels.

5. Grinding When Changing Gears

Low transmission fluid levels can also cause grinding when trying to change gears especially in manual transmissions.

Since the main job of transmission fluid in manual transmissions is to keep the transmission gears lubricated if there is low or no fluid in the transmission you will have metal on metal contact between the gears which can result in grinding when changing between gears.

6. Red Fluid Leaking From Car

Transmission fluid like I mentioned is red in color so if you notice red fluid leaking from your car after it’s been parked there is a good chance that your transmission fluid is low.  It’s likely that your transmission has been leaking fluid for a bit and this is just the first time that you are noticing it.

If you ever notice red fluid leaking from your car after having it parked for a while it’s always a good idea to check the transmission fluid levels in the transmission and then see what you can do about getting the leak fixed.

Can Low Transmission Fluid Cause Stalling?

Usually low transmission fluid won’t cause an engine to stall out, it’s more likely that there is a problem with the air or fuel systems of the engine causing the engine to stall. However, if the torque converter in an automatic transmission isn’t working properly it can cause the engine to stall.

This is because the torque converter functions the same way a clutch would in a manual transmission car. Solenoids in the torque converter can malfunction which can cause the torque converter to quit spinning when it should not causing your engine to stall out.

Can Low Transmission Fluid Cause No Reverse?

As I mentioned above automatic transmissions rely on transmission fluid to allow them to shift properly.  So low transmission fluid can definitely cause your reverse gear to not work. You may have a larger problem with your transmission but if you no longer can reverse in your car when it previously worked first check your transmission fluid levels.

Can Low Transmission Fluid Cause Limp Mode?

With modern cars they have sensors everywhere that tell the car if a part is malfunctioning or if something is broken, this includes sensors in the transmission.  Sensors in the transmission can determine if the transmission fluid levels get too low to operate the transmission safely and can put the car into limp mode until the issue is corrected.

Can Low Transmission Fluid Cause No Overdrive?

Low transmission fluid levels can cause your transmission to not work properly which can include locking the transmission out of overdrive gear.  If you suspect that your transmission fluid levels are low add more transmission fluid to see if that helps the transmission shift gears properly again.

Can Low Transmission Fluid Cause My Car to Overheat?

Usually, if your car is overheating it’s a problem with the coolant system of the car.  However, if the transmission fluid is low and the transmission is slipping between gears or you are towing something I could see your engine overheating from the added stress on your engine.

Can Low Transmission Fluid Cause a Check Engine Light?

If your car has a generic check engine light instead of a warning light then your check engine light may be illuminated to indicate a problem.  On older cars that aren’t able to digitally display the problem then an OBD2 scanner would need to be used to read trouble codes to determine what caused the check engine light to come on.

How Can You Check The Transmission Fluid Level?

Most cars will come with a dipstick in the engine bay that can be used to check the transmission fluid levels.  However, on some vehicles, there may not be a dipstick in the engine bay that lets you check the transmission fluid levels similar to how you would check the engine oil levels.

On some cars, you actually have to go underneath the car to check the transmission fluid levels on the transmission itself which if you ask me is really a dumb design when compared to a dipstick in the engine bay.

If you are unsure if your vehicle has a dipstick in the engine bay or if you need to check the transmission fluid using another method the easiest way to find out is to check your owner’s manual or do some research online.

How Long Can A Car Run Without Transmission Fluid?

It’s never a good idea to operate a car without transmission fluid in the transmission.  Doing so will likely damage the transmission resulting in costly repairs to rebuild or replace it.  While you may be able to drive down the road with no transmission fluid with a manual transmission if you have an automatic transmission you likely won’t be able to drive the car at all.

How Often Should You Change Transmission Fluid?

Most vehicle manufacturers recommend that you change your transmission fluid every 30,000-50,000 miles.  To find out what mileage your vehicle manufacturer recommends changing your transmission fluid you can check the owner’s manual or search for your specific make, model, and year of car online to see what’s recommended for it.

It’s important to follow the recommended change intervals for transmission fluid especially if your car is still under warranty.  Otherwise, you risk voiding the warranty on your car. I usually change the transmission fluid in my car every other oil change because it’s not that difficult to do in my car and it’s fairly cheap to do myself.

What Does A Bad Transmission Sound Like?

When a transmission is going bad you can usually hear weird spinning or swirling noises coming from the transmission shifter.  Any clunking or grinding noises coming can also be a bad sign coming from your transmission.  Having your engine rev up while shifting is also a sign that your transmission is slipping between shifts and it could be going bad.

How Can I Tell If My Transmission Is Going Out?

Automatic Transmissions

Over time like all things that are mechanical transmissions will start to break down and will eventually stop working altogether.  Automatic transmissions contain clutch packs that will start to wear down over time. These clutch packs are essentially the same material that is used in brake pads, which if you didn’t know also wear down and need to be replaced over time.

As these clutch packs wear down your transmission will start to slip or jerk when changing gears because the clutch packs will no longer have the pad material on them needed to grip against the torque converter in the transmission.

When these clutch packs get worn down enough eventually your car won’t change gears at all, which means that you will need to either rebuild or replace the transmission.

Manual Transmissions

With manual transmissions, they use one clutch disc that can also wear down over time but is usually easier to replace than with automatic transmissions.  If you notice that your car is no longer putting the power down to the ground like it used to and is slipping gears and you have a manual transmission it’s likely that your clutch needs to be replaced.

Usually with manual transmissions when they are going bad they will hesitate to go into certain gears or grind when going into gear. When this happens this usually means that the synchros of the transmission are shot and need to be replaced.  But there could also be a problem with the shifting fork.

Manual transmissions that are going bad can also make weird noises while in gear and driving normally. If your manual transmission is showing these symptoms it’s likely that it will need to be rebuilt or replaced soon.

How Much Does It Cost To Replace a Transmission?

Replacing a transmission on a car is not cheap.  Typically it can cost anywhere from $2,000-$3,000 to have your transmission rebuilt or replaced.  Depending on your situation you could also look at having your transmission replaced with a used one but usually, it’s best to have your transmission rebuilt unless you know that the used transmission works.

Should You Flush or Change Transmission Fluid?

The question regarding if you should have your transmission fluid changed or flushed has been asked by plenty of people.  Really you should do what your vehicle manufacturer recommends for your specific vehicle.

But just know that with a transmission flush transmission fluid will be pushed throughout the transmission and there is a chance that debris in the transmission will be pushed into areas that it should not which could plug up parts of the transmission.  To learn more about if having your transmission fluid changed or flushed is right for your car check out my other article (link here).