Is a Transmission Flush Necessary for My Vehicle? | YourMechanic Advice (2025)

FAQs

Is a Transmission Flush Necessary for My Vehicle? | YourMechanic Advice? ›

It's generally recommended that you perform a transmission flush on your vehicle every 30,000 to 60,000 miles. This helps promote the smooth operation and longevity of your transmission while minimizing the likelihood of a mechanical breakdown.

Depending on what the manufacturer recommends, you may need to get a transmission flush every 30,000 miles or two years. In some cases, your owner's manual may suggest waiting until your car reaches 100,000 miles. Your best bet is to check your manual and consult with our technicians.

Without clean fluid, the inconsistent flow will prevent gears and moving parts from shifting cleanly and correctly. Gear Trouble: If your gears are slipping or you are struggling when shifting gears, your transmission fluid might be the culprit.

If you've neglected an automatic transmission oil and filter changes, then leave it alone. The reasoning for this is transmissions develop a varnish inside of them, from the oil film. By changing the oil and filter, you're placing a new corrosive oil that's designed to keep the oil galleys clean.

Signs You Need A Transmission Flush

Other than the obvious check engine light, if you observe slipping gears, transmission whine, delayed shifting, or poor acceleration, then you might want to consider having the transmission fluid changed or perhaps even flushed.

Many auto manufacturers suggest having an automatic transmission flushed once every 30,000 to 100,000 miles. For a manual transmission, it usually ranges from 30,000 to 60,000 miles. It's worth noting that some manufacturers don't recommend a flush at all, at least for certain models.

Drivers can expect to pay $125 to $250 for a transmission fluid flush service. This is approximately twice as much as a transmission fluid change. This is due in large part to the additional fluid required. A flush will take 12 to 22 quarts, while a fluid change requires 5 to 7 quarts.

Despite some potential advantages, a transmission flush also carries certain hazards which, if not properly managed, can potentially worsen existing transmission problems or create new ones. Power flushing, for instance, utilises force to expel old fluid and contaminants.

If your fluid has never been changed before, replacing it with new fluid can cause the transmission to start slipping, even if it wasn't slipping before. This is because the old fluid will contain clutch material from being in there over time and can actually be helping the transmission to still shift gears.

Many transmissions fail after a transmission flush, not because of the flush, but because the transmission was already at the threshold of failure. A transmission flush is not intended to fix transmission problems, it is meant to help maintain the transmission.

Should I flush my transmission after 100k miles? ›

In the past, the factory-recommended interval for changing the automatic transmission fluid was typically between 30,000 and 100,000 miles, but some newer vehicles have what's referred to as “lifetime fluid.” However, there's some question as to whether never changing the transmission fluid may shorten that “lifetime.” ...

If you drive manual, most manufacturers will recommend changing your transmission fluid every 30,000 to 60,000 miles. If you have automatic, you can typically boost that range up to 60,000 to 100,000 miles. There's no harm in changing your fluid early.

Changing the fluid on a regularly driven vehicle can only help revitalize the clutch material. If the fluid has never been changed on a regularly driven car, at 170,000 miles, you damn well need to completely flush the system!

And some people warn against performing a flush on a transmission using old, dirty fluid. The flushing procedure may cause some fluid to move in the opposite direction of normal flow due to eddy currents, which may increase the risk of dislodging debris and causing it to settle somewhere it shouldn't.

After a transmission fluid flush, you may notice that your vehicle shifts smoother, and that your transmission operates better than before.

A trained mechanic can perform a simple transmission flush in three to four hours using a commercial flushing machine or pump inlet. A transmission fluid change takes just about 30 minutes.

Performed properly, a transmission flush will not damage a transmission. Are transmission flushes a waste of money? No! Transmission fluid flushes remove contaminants that could hurt your transmission, much the same way that engine oil is changed to clean the engine.

If you decide to have a system flush performed on your transmission, it is important to hire a trained professional. If not performed properly, more harm than good can be done to the components of the transmission.

If your fluid has never been changed before, replacing it with new fluid can cause the transmission to start slipping, even if it wasn't slipping before. This is because the old fluid will contain clutch material from being in there over time and can actually be helping the transmission to still shift gears.