Transmission Flush vs Change: What is the Difference? (2024)

What is a Transmission Flush?

A transmission fluid flush is a service that exchanges all the fluid inside the gearbox with new, clean fluid. It’s a procedure that normally takes an hour or less and requires equipment that you’ll find only at a professional shop. At the heart of it, the old fluid is pushed out of the transmission and tranny oil cooler and collected for disposal, then it’s filled with new fluid.

The idea behind the transmission flush is to remove as many contaminants and impurities as possible with a process that’s fast and relatively not intrusive.

How a Transmission Flush is Done

Again, the transmission fluid flush needs special equipment to do the job. These are the steps:

  • Get the transmission to operating temperature with a transmission flush additive mixed with the old fluid.
  • Disconnect a transmission fluid hose, typically somewhere accessible like the transmission cooler.
  • Connect the fluid exchange machine inline.
  • Fill the fluid exchanger with the correct type of transmission fluid for your vehicle. Typically you’ll need twice the volume.
  • Run the machine. It circulates clean fluid into the transmission while expelling the old fluid into a storage compartment in the machine.
  • New fluid flushes contaminants out of the transmission as the old fluid leaves.
  • The new fluid enters the transmission and is topped up to the correct level.
  • The machine is removed, and the hose is re-connected.

The transmission flush is almost 100% effective at changing the fluid in the transmission in under an hour.

What is a Transmission Fluid Change?

Changing the transmission fluid sounds simpler than a flush, but the process is actually longer and more involved. It takes about 90 minutes for a DIYer to tackle, and you can do it with common hand tools or power tools. The crux of the job is changing much of the fluid as well as changing the filter and getting a read on any issues that could be present.

What a Transmission Fluid Change Includes

A transmission fluid change, on the other hand, does not need specialty equipment and can be performed either by a professional, like at one of our Preferred Shops, or by a DIYer. This is what it looks like:

  • With the vehicle on a hoist, carefully remove the transmission oil pan.
  • Be prepared with a drain pan to catch the fluid. It can get messy!
  • Remove the gasket or silicone sealant from the mounting surfaces, then clean the tranny pan with brake cleaner and lint-free shop towels.
  • Remove the transmission filter, cutting it open to check for large particles or metal shavings.
  • Locate the magnet inside the oil pan, checking for excess steel particles or chunks that shouldn’t be there. Clean it off.
  • Install the new filter, then install the gasket or sealant before re-installing the transmission pan.
  • Fill the transmission via the dipstick or fill hole in the case to the level indicated in the owner’s manual.

The transmission service only removed about 70% of the old fluid, but it serves to remove contaminants trapped in the filter and on the magnet. It also re-seals the pan.

What is the Difference Between Transmission Flush vs Change?

Both services are meant to change the fluid, so what’s the big difference?

A transmission flush is like performing a oil change by draining and refilling the engine oil alone – no filter replacement. A trans fluid flush serves a purpose but it isn’t as thorough. It’s also not as intrusive, and some would argue that it can prevent fluid leaks at the pan gasket.

And while a transmission fluid change – also called a transmission fluid service – doesn’t remove fluid stored in parts aside from the transmission like the oil cooler, it removes some of the particles that can plug up a filter or continue to circulate in the new fluid. As well, there’s peace of mind that comes from seeing little to no debris stuck to the magnet, or if there is, it’s an early warning sign that can save money on major transmission repair later.

When Should a Transmission Fluid Change be Done?

Generally, a transmission service, whether a fluid change or flush, should be performed around 30,000 to 100,000 miles on an automatic transmission. That’s a wide range, obviously. Specifically, you should identify the interval for transmission servicing for your vehicle based on the information in your maintenance guide, ensuring you adjust for normal or severe service depending on the conditions you drive in.

Will a Flush or Fluid Change Fix Transmission Issues?

A transmission flush or fluid change is a preventative maintenance item, not corrective. If you’re already having symptoms or transmission issues, there’s only a slim chance that it could fix what ails you – and that’s if the fluid is low. Odds are very high that transmission symptoms will be due to some type of failure inside the transmission that could be from lack of maintenance, unfortunately.

What You Can Do

Is it time to change the fluid in your transmission? We have what you need. Get your transmission fluid at AutoZone and get trusted advice from associates to get the job done right. If you determine the job is too big to tackle, check out our list of Preferred Shops in your area to help you complete the job.

Frequently Asked Questions

Should I get a transmission flush or change?

A transmission flush can be a good solution for routine maintenance, but a fluid change offers benefits too. If you can’t afford the full fluid change, at least get the fluid flushed on time.

What’s the difference between transmission flush and just changing the fluid?

A transmission flush exchanges all the fluid in the transmission, lines, and oil cooler but leaves other key items untouched. A transmission fluid change also changes the filter and oil pan gasket while changing around 70% the fluid.

Can transmission flush damage the transmission?

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.

Is it good to change transmission fluid on high mileage vehicles?

It’s a good plan to maintain a transmission regardless of the mileage on the odometer to keep it operating well as long as possible.

Transmission Flush vs Change: What is the Difference? (2024)

FAQs

Transmission Flush vs Change: What is the Difference? ›

With a flush, all the old fluid is removed by a flush machine and replaced with new fluid, allowing for optimal transmission performance. A fluid change is a drain-and-refill, with some old fluid remains in the transmission after the change, which can contaminate the new fluid — and diminish performance.

Is it better to do a transmission flush or change? ›

A transmission flush is better than a transmission fluid exchange. On average, a transmission fluid change drains less than half of the total fluid in your transmission. This is because your transmission has many nooks, crannies, and fluid lines where your transmission fluid can stay stagnant.

How do I know if I need a transmission flush or a new transmission? ›

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.

What is the downside of transmission flush? ›

A theory here is that flushing can dislodge debris that's trapped in some of the internal passages, allowing it to clog up other passages downstream. It could also blow out old seals that are otherwise doing their job.

How much is a transmission fluid change vs flush? ›

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.

Why do transmissions fail after flush? ›

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.

What mileage is good for a transmission flush? ›

What is the recommended service interval for transmission flushes? Each manufacturer recommends the transmission flush interval for their vehicles; however, most recommend that the transmission is flushed every 30,000 to 50,000 miles.

Does your car run better after a transmission flush? ›

A transmission flush gives your mechanic the opportunity to inspect the transmission system and head off bigger problems by finding small ones early. Finally, the increased fuel efficiency and smoother shifting will make the vehicle feel like it's running better on the whole.

What happens if you never flush transmission? ›

The main thing that happens if you don't change your transmission fluid is that the system can overheat and cause a system failure. Low transmission fluid can also delay or cause difficulty in shifting, which can prevent your vehicle from accelerating or operating correctly.

Should I change my transmission fluid if it's never been changed? ›

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.

Does a transmission flush extend the life of a transmission? ›

This can enhance your vehicle's overall performance and fuel efficiency. Extended Lifespan: Regular transmission flushes can help prolong the life of your transmission. By removing harmful contaminants and preventing overheating, you reduce the risk of costly repairs or replacements.

How many years does transmission fluid last? ›

Automatic: Every 60,000 to 100,000 miles

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.

Can I change my transmission fluid without changing the filter? ›

However, ideally, you'll want to change your filter before any of these problems come up. Keeping that in mind, it's recommended that you change your transmission filter whenever you have to perform a transmission fluid change. Usually, your owner's manual will inform you when you need to do this.

How do I know if I need a transmission flush or new transmission? ›

If a transmission has too much dirt or sludge in the fluid it can cause a sluggish response when shifting gears. It may be time to flush the transmission fluid in an automatic if the car changes gears too quickly or too late. Manual transmissions that need a flush may be hard to shift at all.

Which is better, transmission flush or change? ›

Flush — Which to Choose? It's been said that a transmission flush is more effective than a change because: With a flush, all the old fluid is removed by a flush machine and replaced with new fluid, allowing for optimal transmission performance.

Does Jiffy Lube change or flush transmission fluid? ›

Changing transmission fluid yourself can be a messy, complicated process. Save time and energy with a transmission fluid exchange appointment at your nearest Jiffy Lube®. A trained technician will remove the used fluid and replace it with new transmission fluid that meets or exceeds your manufacturer's specifications.

Does changing transmission fluid improve performance? ›

The importance of regular transmission fluid changes in improving vehicle performance cannot be overstated. They can help reduce fuel consumption, prevent potential damage to the transmission system, extend the lifespan of the car, and provide a smoother, more enjoyable driving experience.

Can I add transmission fluid without flushing? ›

While you may be able to get by with a simple transmission fluid change instead of a full flush when you need a quick fix, it won't protect your transmission for too long. Meaning it is not the best way to ensure the longevity of your vehicle. That is why you need a complete fluid flush and replacement.

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