In today’s day and age, there is no longer an industry standard for how often you need to change your transmission fluid. So, if you’re wondering, “when do I need a transmission flush?” you won’t find an exact answer here. Instead, you’ll get armed with enough knowledge to keep your car running well.
First, What Does Transmission Fluid Do?
The fluid actually serves many purposes. Not only does it lubricate the internal gears and components on the transmission, but it also acts as a coolant, and is used to transfer power from the engine to your wheels.
Automatic transmissions run very hot internally, and the fluid breaks down over time. It is hydroscopic in nature, which means it can absorb moisture from the outside as well. Thus, it does need to be changed fairly frequently.
So, When Do I Need a Transmission Flush?
1. Check Your Owner’s Manual!
Manufacturer recommendations vary from ‘every 24,000 miles,’ to ‘every 100,000 miles.’ In most cases, if you wait longer than 60,000 miles, you’re asking for trouble.
The best rule of thumb is to follow your owner’s manual. It will have all the required maintenance service intervals listed. If you do this, you can’t go wrong.
The manual will also include the specific fluid requirements. Using the incorrect ATF (Automatic Transmission Fluid) can result in major transmission drivability issues, or even a very expensive transmission replacement.
2. Don’t Just Look at Fluid Color
The days of saying transmission fluid is always red are gone. Depending upon the type of ATF needed, transmission fluid can come in blue, green, or clear.
You can no longer just take a look at the fluid to determine whether it’s time to flush it out.
3. You May Not Be Able to Check the Fluid Level
Many manufacturers are doing away with dipsticks because they do not want the “Average Joe” to mess with the fluid level.
If you do find a dip stick, remember to check to fluid level when the car is running (in park with emergency brake on) for a while. ATF expands when it’s hot and if the car is cold you will not get a proper fluid level reading.
What’s The Difference Between a ‘Transmission Flush’ and a ‘Transmission Drain and Fill’?
A transmission flush is done with a machine that pushes fluid through the entire transmission and cooling lines to force out the old fluid. Some manufacturers recommend against flushes because some machines flush the fluid in reverse direction. This can lead to loosening of debris in your transmission; these in turn can block and clog important pathways. The debris can cause the transmission to shift improperly.
Transmission Drain and Fill
Draining just uses gravity to remove the fluid. Drain and fills are often significantly less expensive than transmission flushes. Unfortunately, when draining, not all of the fluid is removed, which could be detrimental to your vehicle.
Which Do I Need?
Again, consult your owner’s manual! It should specify which is better for your vehicle.
Ok, I Need a Transmission Flush (or Drain), Now What?
As you’ve now seen, clean transmission fluid is extremely important to your vehicle. If maintained improperly, the fluid can cause significant and expensive damage. Replacing your transmission fluid is a service that should always be performed by a certified mechanic, and not done in your own backyard.
Ready to get your transmission serviced?