Automatic transmission fluid (ATF) is the red-headed stepchild of automotive repair. Car owners who don’t get their engine oil changed regularly are practically non-existent. Those who track the last time their ATF was changed are part of a distinct minority.


Automatic transmissions were invented to take the burden of shifting gears for those who wanted uninvolved motoring. The first examples were troublesome and inefficient. Lower fuel mileage in automatic transmission-equipped cars was why, until recently, many owners opted for manuals.

Recent innovative technology, such as automatic emergency braking that requires an automatic transmission to interface with, has resulted in many manufacturers stopping manual transmission production.

So since we will be using automatic transmissions from now on (electric cars use them), let us get familiar with the fluid that keeps them healthy.

You have probably noticed that when your car is stopped with the engine running, there must be some slippage in the drivetrain, or else the engine would stall. This is made possible by a fluid connection between the engine and the rear axle. The modern automatic transmission incorporates a torque converter that performs this function and more.

ATF Isn’t All the Same

For the torque converter to work properly, the transmission must contain the right kind and amount of ATF. There are several types of ATF, and putting the correct type in your car is critical. If you want to keep a quart of the right stuff in your trunk, see your owner’s manual or speak to our technician.

How Long Does ATF Last

Like your engine oil, ATF has a service life. The length of ATF service life depends on several factors you need to consider for your transmission to last as long as the rest of your car.

ATF Leaks

The reason for a low ATF level is a leak. Your engine may use or burn its oil, and automatic transmissions do not. Diagnosing a low transmission fluid level is so easy some manufacturers do not provide a dipstick.

If you have an ATF leak, a red fluid puddle will be on your driveway. But since your ATF may be heavily contaminated, the bright red color of new ATF may have turned to dark brown.

You may be unable to tell the difference between leaks of old contaminated ATF and engine oil. Trust us to notice the difference. By the way, the manufacturers who removed transmission dipsticks have an internal ATF level sensor to set off an ATF low-level light on your dashboard.

Overheated ATF

Another reason for transmission problems is overheated fluid. This item is of critical importance. Vehicles designed to tow, such as pickup trucks, frequently have ATF temperature gauges. Other cars have an ATF overheat light to warn you of this circumstance.

If you often tow a trailer, consider an aftermarket transmission cooler. If you know you overheated your ATF, consider bringing your vehicle to us for service.

ATF Service

ATF is supposed to be changed along with the internal filter at regular intervals, often every two years or 24,000 miles. We frequently see older cars where the ATF has never been changed. Neglecting this preventative maintenance is poor economics. A transmission rebuild is many times more expensive than an ATF drain and flush service.

Trust us to look after your investment in a motor vehicle. Visit our website or call us for an appointment for a transmission service or any car-related matter of your concern.