quick A/T fluid change question

[jkoni426]

I've looked at a bunch of the write-ups about flushing and just doing a drain and fill. I wanna do the flush method by disconnecting one of the cooler lines, but I'm wondering if I also have to do a drain and fill before or after flushing to get ALL the old fluid out. The write-ups I've read didn't really seem to address this (unless I missed it).

thanks,

Joe

 

[kball]

Do a drain and fill first, then start pumping it out the cooler line.

 

[jkoni426]

^ awesome thanks. Wasn't quite sure if the flush alone would pull the fluid from the pan or not.

 

[t4r4life]

yeah i would't flush it if it has too many miles, often does more harm than good.

 

[kball]

^ awesome thanks. Wasn't quite sure if the flush alone would pull the fluid from the pan or not.

Yes it pulls from the pan so you might as well put new in the pan to start with rather than pull old all the way through.

 

[jkoni426]

^ Haha yeah that makes sense, guess my newbness is showing.

The truck's got 216k with kind of an unknown history. I've seen write ups where it says if it smells burnt don't flush it but the FSM says if it smells burnt to change it. So I was kind of hesitant to do it but figured I would. It's definitely dirty but I can't tell if it smells burnt.

 

[t4r4life]

when you do ATF you will never change all of it, majority of the fluid is stuck in the TQ converter so when you replace fluid you're just adding a bit new fluid everytime, still better than just having old fluid. but if you have 216k then i'd say you tranny has done it's job. i've seen 3rd gen tranny give out as early as 180k

 

[RHeld24]

Sounds like extra work and possibly wasted ATF. The system circulates all of the fluid any way, what would be the difference in putting new ATF in the pan vs. pouring it in during the flush?

 

[jkoni426]

I thought the flush DID get the fluid from the torque converter?

 

[jkoni426]

Sounds like extra work and possibly wasted ATF. The system circulates all of the fluid any way, what would be the difference in putting new ATF in the pan vs. pouring it in during the flush?

yeah that's exactly what I was wondering

 

[t4r4life]

I thought the flush DID get the fluid from the torque converter?

yeah a flush does but a drain and fill doesn't. also great username lol

 

[kball]

Why not start with as much new fluid as you can? Why suck old fluid from the pan through the system? It won't hurt anything but there's no sense sucking 4 quarts of old fluid through the system if you don't have to. A drain and fill of our tranny's is about the easiest thing you can do so why not? Get rid of 4 quarts of bad fluid the easy way right off the bat!

 

[RHeld24]

And I agree with t4R4life, if you're hesitant about doing a full flush with the current condition of the trans, then just drain and refill more often than usual (especially if the trans is working fine). That way you slowly improve the quality of the ATF instead of jumping straight into brand new ATF that may affect the trans (whether that effect be good or bad).

 

[RHeld24]

Why not start with as much new fluid as you can? Why suck old fluid from the pan through the system? It won't hurt anything but there's no sense sucking 4 quarts of old fluid through the system if you don't have to. A drain and fill of our tranny's is about the easiest thing you can do so why not? Get rid of 4 quarts of bad fluid the easy way right off the bat!

I was just thinking that if he drives the truck on a normal basis that the "old" fluid in the pan is just the same as the rest of the fluid in the entire system and wouldn't harm anything by passing through during the flush.

Either way, you end up with clean fluid so I don't think it really matters. I thought it may save him a little time and money...

 

[kball]

I was just thinking that if he drives the truck on a normal basis that the "old" fluid in the pan is just the same as the rest of the fluid in the entire system and wouldn't harm anything by passing through during the flush.

Either way, you end up with clean fluid so I don't think it really matters. I thought it may save him a little time and money...

Yes I agree, either way works fine. But doing the drain and fill actually saves time since you aren't waiting for the 4 qts of old fluid from the pan to circulate out the cooler line. Once the good fluid from the pan comes out the cooler line you are done.

And we need to stop calling this a "flush" because it is confusing people. Running the engine and letting trans fluid pump out the cooler line is basically a more complete drain and fill.

What people think of when "flush" is used is when it's hooked up to a machine that powers the fluid through and can dislodge chunks of material/sludge that can cause damage.

Draining and filling using the cooler line method is no more harmful than driving the truck.

 

[jkoni426]

nothing seems to be wrong with the trans but I wanted to change the fluid because of its unknown history and just preventative maintenance because it's dirty.

I should need about 3 gallons of dex III right? Any advantage to using toyota atf over say valvoline?

thanks again for all the comments.

 

[kball]

3 gallons should be good. Get Valvoline Maxlife or whatever brand of Dex VI. The Maxlife should be much cheaper.

 

[Joshv4runner]

I would do just a drain and fill to be on the safe side.

 

[jkoni426]

^a drain and fill by itself just seems pointless to me since you're only replacing like a third of the fluid...

 

[t4r4life]

^a drain and fill by itself just seems pointless to me since you're only replacing like a third of the fluid...

depends on you look at it, but it's just advice, the op can do whatever the fuk he wanna deeeewwww!