You might not know how low transmission fluid poses a potential problem. Most modern cars don’t even have transmission fluid dipsticks anymore, and some manufacturers claim the fluid inside will stay good for the lifetime of the gearbox.
However, when your car starts making odd noises and having trouble shifting, its transmission fluid can likely be to blame.
What Is Transmission Fluid?
To function smoothly, transmissions require special fluids to provide lubrication and cooling for the parts that transfer power from the engine to the wheels. It’s an essential component for both manual and automatic transmissions, though the fluid may pull double duty in the latter. What’s more, the fluid may also run at specific pressures to actuate gear changes and operate the torque converter.
As for the appearance of the fluid, it’s typically red, though that can vary according to the manufacturer and the type of transmission it’s designed for. Transmission fluid should have a neutral odor and be the consistency of motor oil. If it’s thick and sludgy or smells burnt, there’s a problem.
How to Tell if You Have Low Transmission Fluid
Assuming you can’t observe the transmission fluid level, here are some signs to look for that denote low transmission fluid levels:
1. Hard or Sluggish Shifts
Typically, when shifting in manual transmission vehicles, the gears have plenty of fluid to cushion their movements, and the lever moves cleanly. When fluid levels drop, the problem presents itself by making shifting more difficult, requiring greater effort while making noticeable grinding sounds.
For automatics, shifts will come slowly. You might shift into drive and have to wait three seconds before the car is in gear, and even then, the transmission may slip out of gear entirely.
Without any transmission fluid, temperatures will rise. The friction of the gears will increase to the point that you’ll smell smoke, power will drop, and shifting will become difficult or outright impossible. Gears can start to produce shavings, which can lead to catastrophic failures and severe damage.
3. Excessive Noise
Grinding, clunking, or whining sounds indicate that the clutches and bands aren’t getting enough lubrication. Transmissions should operate silently, and these noises can mean you need to have the fluid flushed or topped off.
4. Fluid Is Leaking
One of the benefits of transmission fluid is that you can spot it when it pools under your car. If you notice a reddish liquid wherever you park, it’s a good sign that you have a transmission fluid leak. Not only will the lowered fluid level cause the problems listed above, but a leak also means contaminants can get inside your transmission, causing even more issues.
What to Do When You Have Low Fluid Levels
Unfortunately, you won’t be able to refill the fluid without dismantling your transmission, so if you suspect you have low fluid levels, your best bet is to take your car to a repair shop. If the problem is severe enough that you think you will damage your car by driving it any farther, call a tow truck.
Summary: Even though many modern transmissions are sealed by the factory and feature no dipstick, you might not get the “lifetime” of performance you’re promised. If you notice leaks, poor shifting, and odd noises, you might need a transmission fluid refill.