Change or Don't Change Trans Fluid?

[Jarwulf]

99 Camry LE 4 cylinder 2.2L 200000 miles

I know I've changed my transmission fluid but I'm not sure when. How much truth is there in the idea that you shouldn't change your transmission fluid ever again if it hasn't been changed after a certain amount of miles? What would be the mileage?

[asphalt victory]

Thats a myth the problem comes from people trying to fix a problem in theyr trans WITH a fluid change OR adding the wrong type / ammount

Now your saying its dirty...Do you think the transmission fluid is still doing its job? Wouldnt you think your transmission would benifit from fresh clean fluid?

[carsrus]

You can drop the pan, clean it up, new filter and gasket whenever.

Its a flush that can dissolve so much gunk and varnish the trans will grenade. Pan drop only changes 40% or so of the fluid so it clean much more gradually.

[WaxonWaxStillOn]

There's a lot of "can happen" stories but I've never seen a "personally has happened" narrative in posts I've read while researching this on various googles/forum searches, including posts from long time mechanics that have never seen it happen.

Supposedly, if a transmission is on it's last leg, changing the fluid completely can potentially shorten that last leg...atleast that's what I've concluded from what I've read. But since it's rare, there are lots of different theories of when it could happen.

[fenixus]

well generally I think that changing fluid in 99% of cases will do only good, especially if done on regular basis... that's called maintenance .. oh and there is no such thing as "lifetime" fluids ... or rather the definition of "lifetime" is misunderstood (usually in dealer's terms lifetime=100k miles).

however, if somebody totally completely neglected the transmission for 200k miles (if that can survive that long without breaking down) then yeah ... flushing the fluid can "harm it" meaning that probably all that crap, gunk, shit, dirt and additives inside it is needed to hold it back together and fill the excessive oil clearances and somewhat buildup some pressure ... but then again if someone neglected it THAT bad in first place, why would they care about such a nonsense as changing the fluid after all, huh?

[Silent Runner]

I think that changing trans fluid is almost always going to extend the life of a high mile/service, neglected atm, but I suppose that there is a remote possibility that fresh fluids (with a fresh dose of detergents), could loosen up some muck that might interfere with the hydraulics. Or maybe the fresh fluids could start engaging clutchs in a more firm and timely manner and quickly finish off heavily worn components... But such a failure would imply that it was ready to let go really soon anyway. It would take a serious forensic investigation to tell if a fluid change ever actually caused an automatic transmission to fail.

[bigbird]

I choose "dont know" because you left it as an option. Like others have said, I have never seen anyone have issues after a drain and fill. Flush is a different story. I have seen a couple trannys go south with high mileage after one. But thoes trannys were likely to do so anyways.

[mail2_jb]

I recently changed my ATF and Diff fluid (after checking TN of course) and so far car is running great (95k and 83k miles). I didn't know that you should be changing these fluids and my dealer never talked about it. Anyhow, i am planning to change them every year or 15-20k miles, it is just 20$ for mobile1 and I bet the trans will last a lot longer if proper fluid change is done.