Is it necessary to completely flush automatic transmission fluid?

[lupindub]

So I just read the shop guide on how to change ATF on our cars and it's a bit of a pain in the ass. So is it possible to simply drain once, then fill up however much you took out without drain/overfilling 3 times? I am planning on changing the ATF every other oil change if that counts as anything. Is this a viable option or will it eventually ruin my tranny?

Basically what I want to do is ONE drain and ONE fill, aprox. every 15,000 miles and wondering if the frequency of the change can compensate for the FULL transmission flush like the manual recommends?

[humfrz]

Well, now @lupindub, that would be like changing the crankcase oil a couple of quarts at a time.

I reckon a "limited change" would be better than no change at all.

However, putting in some new fluid, mixed with the old fluid just doesn't seem to the best way to go .... to me, at least.

That would be like changing your underwear by turning it inside out .....

I would suggest that if you are going to change the ATF, do it like the manual suggests .....


humfrz

[Wayno]

Originally Posted by humfrz

I would suggest that if you are going to change the ATF, do it like the manual suggests .....

It doesn't, as it's "lifetime" fill.


Doing drain and fills every so often is just fine and should save you from having to eventually go to a transmission shop to have it flushed (with a machine).

Be sure to get the service manual and do the level adjustment properly or you will have shifting issues.

[Tcoat]

Originally Posted by Wayno

It doesn't, as it's "lifetime" fill.


Doing drain and fills every so often is just fine and should save you from having to eventually go to a transmission shop to have it flushed (with a machine).

Be sure to get the service manual and do the level adjustment properly or you will have shifting issues.

Nope not the AT. Replace at 60K miles:

[humfrz]

Originally Posted by Wayno

It doesn't, as it's "lifetime" fill.


Doing drain and fills every so often is just fine and should save you from having to eventually go to a transmission shop to have it flushed (with a machine).

Be sure to get the service manual and do the level adjustment properly or you will have shifting issues.

Well now, @Wayno ..... maybe that's what it says in the manual for your Australian 86, but the manual for my (US) 2013 FR-S recommends to change the ATF every 60,000 miles (like @Tcoat 's manual says).

Maybe you were thinking of the coolant .. ??

As far as changing a little bit of the ATF at a time .... why half ass the fluid change ......


humfrz