When you’re running low on transmission fluid, your vehicle can’t function the way it’s supposed to. This is because transmission fluid lubricates the surfaces and components of the transmission system to reduce friction and prevent them from wearing out.
If your transmission fluid is low or in bad shape, it can cause serious problems to your car’s transmission. Here are some common symptoms of low transmission fluid. Pay attention to these because you may be facing an expensive repair in the future otherwise.
Common Low Transmission Fluid Symptoms
You’ll find that pretty much all signs of low transmission fluid point to a transmission fluid leak as the cause. If any of the following symptoms show up, the first thing you should do is check the transmission fluid level to confirm.
While you’re at it, check the condition of the fluid. New transmission fluid should appear bright red and almost transparent.
If the color is brown or darker, you may have internal problems. See our transmission fluid color chart to see what the color of your fluid says about its condition.
#1. Transmission Fluid on Garage Floor or Driveway.
This sign that you’re running low on transmission fluid is pretty obvious but often overlooked. When you notice a small puddle or spots of a red or brown fluid underneath your vehicle where your engine and transmission sit, you likely have a transmission leak.
This is usually due to a worn or damaged transmission pan gasket, loose drain plug, or even damage to the transmission pan itself.
Some leaks are incredibly minor, and while you eventually want to fix them, keeping an eye on your transmission fluid level and topping off when needed will get you by. But for most leaks, you want to take care of the issue right away.
#2. Slow Gear Engagement.
With low transmission fluid in your vehicle, you will sometimes notice a temporary delay after you move the gear lever into reverse or drive. The reason being is that the gear shift cannot take place immediately if there isn’t enough transmission fluid pressure.
With low fluid, it make take an extra 1-2 seconds to build enough pressure for the gear change. This same symptom will appear if there’s a problem with your transmission valve body so if you confirm the ATF level is fine, that’s another possible cause.
#3. Trouble Shifting Gears.
Manual and automatic transmission vehicles both must have transmission fluid that is clean and able to flow freely inside of your transmission. If your transmission fluid is contaminated by dirt or other material, then its response will be very laggy and sluggish.
Once that starts happening, your gear shifting will cause the gears to change too fast or too slow as you’re driving the vehicle.
If you are driving a car with a manual transmission, it could be very difficult for regular gear shifts and you may not even be able to get into certain gears at all.
#4. Strange Noises While in Gear.
A properly operating transmission should be silent to the driver. But if you start hearing rattling noises or a rhythmic pounding while in gear and not when in park or neutral.
You may have an issue with your torque converter due to the car being low on transmission fluid.
If you hear grinding or clattering while changing gears, it may be another sign that not enough transmission fluid is in the system.
#5. Transmission Overheats.
Similar to how a motor needs the proper amount of engine oil to lubricate all parts and maintain correct operating temperature, the transmission needs an adequate level of transmission fluid to keep it at the normal operating temperature.
With not enough transmission fluid, your transmission will quickly begin to overheat due to excess friction between moving parts. You may notice a strong smell from the burnt transmission fluid or even smoke coming from the area of the transmission.
If you notice either of these while driving, pull your car off the road immediately and let everything cool down for a while. If the temperatures get too high, then you may have serious internal damage and may need a complete transmission rebuild.
Some newer vehicles may even illuminate a transmission temperature warning light to draw attention to the issue. In other cases, your check engine light may illuminate with a code such as DTC P0711 being stored.
#6. Transmission Gear Slippage.
Low transmission fluid could reduce the hydraulic pressure in the system. If you don’t have enough hydraulic pressure, you won’t be able to remain in the current gear that you have selected.
A gear slipping presents itself by the engine jumping to a higher RPM while driving yet the car is not moving any faster. This is often an indicator that significant damage has already occurred to the gear teeth.
#7. Check Engine Light Turns On.
While low transmission fluid doesn’t directly trigger the check engine light (CEL), it can cause other transmission issues that will.
For example, if your transmission is slipping or overheating due to low fluid, your car’s computer may detect these problems and illuminate the check engine light.
If you see your CEL come on, especially in combination with other symptoms mentioned here, it’s a good idea to check your transmission fluid level.
Remember, the check engine light can indicate many different problems, so you’ll need to use a diagnostic tool to read the specific error code to confirm if it’s transmission-related.
#8. Decreased Fuel Efficiency.
When your transmission fluid is low, your transmission has to work harder to shift gears and operate properly. This extra effort can cause your engine to consume more fuel than usual.
If you notice other symptoms in this article and you find yourself filling up more often or your fuel gauge seems to drop faster than normal, it could be a sign that your transmission fluid is low.
The difference in gas mileage may only be slight, so there’s a good chance you may not even notice this sign.
Consequences of Ignoring Transmission Fluid Levels
Choosing to simply ignore the signs of low transmission fluid can lead to major problems down the road. Here’s what might happen if you keep putting off the issue:
Unsafe Driving Conditions
A transmission that’s not working right can be dangerous. You might have trouble shifting gears, which could leave you stuck in traffic or unable to speed up when you need to. This puts you and other drivers at risk.
Serious Internal Damage
Low fluid means more friction and heat inside your transmission. This can mess up gears, clutches, transmission oil pump, and other important parts. What starts as a small problem can quickly turn into something much bigger and more expensive to fix.
Complete Transmission Failure
Keep driving with low fluid, and you’re asking for trouble. Not only will some internal components wear out quicker, parts can completely fail or lockup and there goes your entire transmission. If this happens, you’re looking at replacing the whole transmission (hint: it’s not cheap).
Bigger Repair Bills
The longer you wait to fix low transmission fluid, the worse the damage gets. What could have been a quick fluid top-up or small leak repair can turn into a major overhaul that costs way more.
Shorter Car Life
Your transmission is a big deal for your car. If you don’t take care of it, you might end up having to replace your whole vehicle much sooner than you planned.
And if you want to sell or trade in your vehicle? Good luck with that if you’re having major transmission issues.