Is changing the ATF often bad for a tranny?

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Chris B.

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After reading on here for years I thought that it is best to flush the transmission often to help it last longer. On another forum I was just told by 2 different people that changing the transmission fluid often is actually bad and it will shorten the life of the transmission. The transmissions in the discussion were a 2012 Honda 5 speed automatic mated to a V6 and a 4L60E in a GM half ton truck but I think this applies to all automatic transmissions.
I always thought that changing early on a new car(15,000) miles was a good thing to do for it and every 30,000 miles was also a good practice. So what is the latest thought about this on BITOG? Can changing the ATF early and often do harm to the transmission or is that [censored]? Thanks!
 
Keep in mind there is a drain and refill of the pain which gets about 1/3 of the total capacity and then there is a total fluid exchange (incorrectly called a flush) which gets close to 95%.

When people say "change the ATF fluid", they could mean either.

Given the cost of quality ATF and that a lot of the current OEM ATF is synthetic, I would think 50K would be more realistic for a total fluid exchange.
 
Changing the fluid too often be bad? Yeah maybe if you changed it everyday.

Yeah, it'll hurt 2 things.
1. If ATF fluid changed everyday, you'd probably wear out the drain plug threads eventually
crackmeup2.gif

2. It'll hurt your wallet.
 
ATF in my truck has been changed regularly since new. 175K miles now with thousands of miles of towing. Shifts perfect. I dropped the pan around 148K for the first time and it was super clean with just a little material on the magnet. The filter looked good too, but I changed it anyway.

I think I will keep changing ATF.

My truck's maintenance has been a mix of full exchanges and just changing what's in the pan, but basically fluid is never in there for more than 30K mi.
 
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It's harmless if the work is done properly and done using the proper fluid.

With that said, it is difficult to find transmissions serviced "properly" since many people fail to observe the proper fluid level check procedure.
 
Originally Posted By: Nick1994
Changing the fluid too often be bad? Yeah maybe if you changed it everyday.

Yeah, it'll hurt 2 things.
1. If ATF fluid changed everyday, you'd probably wear out the drain plug threads eventually
crackmeup2.gif

2. It'll hurt your wallet.


Add joint damage if crawling under, and a stiff neck with a lift.
 
Changing ATF (D&R) every 30 to 50K (40K is a happy medium) can only help your transmissions longevity.
 
That's completely stupid. Plenty of 4L60E owners follow a recommended regimen of doing a complete trans cooler line flush every year (5-12k miles, depending on the individual) without any harm at all.
 
I recently had my Ranger Xmsn pan dropped, filter changed, and refilled with about 4 qts (I think the mech said). It was the first change at just under 50K miles.

Does it make sense to use a mity-vac now and then for additional replenishment since there's still a lot of old fluid left?
 
AAMCO dealers are even afraid to flush transmissions,so there is some thing to it.

A drain a refill is okay, its the flush, that is used nowadays that can be risky.

I had a vehicle with 100,000 miles neither firestone or Ammco or Toyota would change the oil.
I did it myself, in 3 intervals, saved a ton on money and was simple. That was over a year ago, but there is rampant fear amongst changing transmission oil if its never been done under 60,000 miles.
 
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Originally Posted By: Chris B.
The transmissions in the discussion were a 2012 Honda 5 speed automatic mated to a V6 and a 4L60E in a GM half ton truck but I think this applies to all automatic transmissions.


Well, there you have it. It was a Honda transmission.
Would anybody blame coolant changes for a GM head gasket failure? I think not.

But i noticed that when it comes to Honda and Toyota, all sorts of theories are conjured so that it is never Honda's and Toyota's fault.
 
Here is one positive experience with frequent ATF changes. This goes back many years.

Company I work for had a 1997 GM G3500 van with a 4L80E transmission. My regimen was to pull the transmission drain plug at every engine oil change (every 5k mi) and replace 4l of ATF. Every sixth engine oil change I would drop the transmission pan, replace the filter and replace about 8l of ATF. I used mineral ATF, not synthetic.

Transmission was flawless in the ten years we had the truck. That transmission got a real work out behind a torquey diesel engine pulling a frequently heavily loaded 1 ton van. The truck went to its grave in 2008 with 300k mi on the odo.
 
Never changed ATF. MY n16 is currently at 80 000km never been changed and we have a toyota hulix with 300 000km and the ATF has been never changed and the transmission is still going strong
LOL im being serious
 
Originally Posted By: Mackelroy
AAMCO dealers are even afraid to flush transmissions,so there is some thing to it.

A drain a refill is okay, its the flush, that is used nowadays that can be risky.

I had a vehicle with 100,000 miles neither firestone or Ammco or Toyota would change the oil.
I did it myself, in 3 intervals, saved a ton on money and was simple. That was over a year ago, but there is rampant fear amongst changing transmission oil if its never been done under 60,000 miles.


I think it's the ramifications of an angry customers I the company for providing a service on an unknown piece of machinery with unknown history. Plus a flush doesn't replace the filter, does it?
 
my uneducated opinion is that any power flush could be bad, and even a normal filter change could be bad if dirt or a piece of gasket gets loose.
Im in the drain and fill camp
 
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