ATF drain and refill quantity: FSM myth or fiction + temperature effect...

[e9999]

well, my FSM says that for my 97 I got to put back in 2.1 US qts. I know some folks here say they put 4 or 5 qts back in (sometimes because that's what they took out - that particular argument seems to me to be a bit less than convincing if one doesn't know if the level is right to start with but anyway).

And yes, of course, there is the question of whether one's dipstick is the right one. Mine has an orange top and is a flexible thin blade with the 4 notches. IIRC previous posts on this, it appears to be OK.

So I started from scratch, did the 2.1 qts. Warmed things up by driving 10 miles, ATF to 160F or so, did the idle and shifting routine and I was just above the upper COLD notch. Not good on that.

So after some trial and error I ended up with 3 qts 7 oz to be right in the middle of the HOT range.

Interestingly, the last time I did this I used 3 qts 8 oz so either I make the same mistake each time and I'm consistent at that or I'm right on.

Interestingly, though, I saw that after I futzed around with adding and checking and adding and checking, my ATF was back down to 120F or so and I was probably reading a bit low. The FSM says you gotta be between 158 and 176F range.

So I checked the temperature effect for your enjoyment and my perverted pleasure:

at 180F I was about 80% of the way up between the 2 HOT notches
at 160F I was about 50% between the 2 HOT notches (in the middle)
at 135F I was right about at the lowest of the 2 HOT notches.

So basically, the temp has a significant effect on the apparent level, watch out for that if you like to be accurate.

I guess the point is that if my dipstick is wrong and the FSM is right I'm a bit above what the correct level should be so I should still be OK, shouldn't hurt any. If my dipstick and techniques are right, well, I'm above the FSM, better be on the conservative side of the FSM right so no worries. If both my FSM and dipstick are wrong, well, all bets are off but at least my trans didn't explode during the last few thousand miles with a bit over 3 qts...

So what do you put in?

 

[CJF]

my dipstick and techniques are right, well, I'm above the FSM, better be on the conservative side of the FSM right so no worries.

This is the only statement (I can't believe I actually read through all that to find it ) that I have a problem with.

From what I've heard/read, an overfilled tranny is worse than an underfilled one. ;p

But of course you're well within spec. regardless, so no worries.

Wait; what was the question??

 

[tomatopants]

The first time I changed my oil, the transmission fluid ended up being drained instead of the oil.



I don't know how much I drained, and I didn't pay attention to how much I put back in.


The funny thing is, I added 3 more quarts of oil, and my oil dipstick said that I was just right. I still drained some out though.


Weird.

 

[e9999]

This is the only statement (I can't believe I actually read through all that to find it ) that I have a problem with.

From what I've heard/read, an overfilled tranny is worse than an underfilled one. ;p

But of course you're well within spec. regardless, so no worries.

Wait; what was the question??

well, my point was that if you don't know whether the FSM is right which it normally is, better be on the too much side than on the too low side with ATF, from what I understand or am guessing about automatic transmissions. I mean if there is too much you're at risk of it spilling, overflowing etc. If you have too low, can't be too good for the converter and mechanicals I'm guessing. So short of serious fire danger I'd rather be too high. Admittedly that is a guess since I'm no trans expert. So I guess if you're thinking the opposite and want to be on low side, how much would you put in since the FSM figure says to put in less than what my (your?) dipstick says? Would you just go with the 2.1 qts then? Maybe not a bad idea if it's not a typo and if you don't trust the dipstick... I'd rather go a bit high so I'm trusting my dipstick on this one.

So basically the main question is that if the FSM says both 2.1 per the table and to fill based on dipstick (which is 3qt 7oz for me), which do you trust? I chose the latter cuz it's on what I think is the safer side. YMMV.

I'm still interested in reading what other folks put in based on their dipsticks, though. (Oh, and never mind the dang supposedly bus trans...)

 

[e9999]

The first time I changed my oil, the transmission fluid ended up being drained instead of the oil.



I don't know how much I drained, and I didn't pay attention to how much I put back in.


The funny thing is, I added 3 more quarts of oil, and my oil dipstick said that I was just right. I still drained some out though.


Weird.

oooookaaaaayyyy......

 

[nakman]

I think you're right on the money.. I usually put exactly 4 quarts in, and only really check it when I've been driving for an hour or so and it's right up at the full hot line. If you jack the front axle up a little then you can get a little more to come out, but my SOP is to do it on the flat garage floor, then 4 quarts. And I've done this at least 6 or 8 times now, and the volume of ATF hasn't accumulated.

 

[CJF]

well, my point was that if you don't know whether the FSM is right which it normally is, better be on the too much side than on the too low side with ATF, from what I understand or am guessing about automatic transmissions. I mean if there is too much you're at risk of it spilling, overflowing etc. If you have too low, can't be too good for the converter and mechanicals I'm guessing.

Seriously, this is what I disagree with.

For example, the FSM for my '84 Cressida (I know this because that tranny seems to be very finicky) states: Do not overfill, or damage to the transmission may occur. Do not underfill, or slipping may occur.

Conceivably (though I admit I don't know this for sure), this means that too much fluid can result in too much pressure and hence damage, while too little fluid can result in too little pressure and hence slipping, but no real damage.

Curtis

 

[gray]

CJF has got it;
overfilling is not good, underfilling, by a little and no problem, by quite a bit, and it may not shift correctly; but you know that right away, and if you're smart, you stop and add some, right away.

When I do a drain and fill, I always would add about 3 quarts, then check the level to see that it was somewhere near where it should be, drive it a few miles, and recheck. Then check again the next day, cold and hot.

Once years ago, I did underfill it (probably by reading the manual) and started to drive away;
I did not get far when the shifting went funky on me; I stopped, checked the level; too low, added ? a couple of quarts; normal again.

However, nowadays, I do complete flushes, but that is a whole other thread,
and argument, and opinions, and, and, and. Works for me.
g

 

[e9999]

I'll gladly learn that I'm wrong and that overfilling could indeed lead to damage, if that can save me from experiencing some carnage. So, exactly what damage is likely to ensue and why?

My FSM says "not to overfill" but no mention of damage that I can see.
Fine, I don't overfill on purpose. That's why I followed (1 of) the FSM instructions.

Anyway, CJ, so, the question remains: do you go by FSM or dipstick or ...? If you are concerned about overfilling, you would take the least of the 2 then I imagine?

Or is it only the 97 FSM that has the 2.1 qts figure?


[damn, I fumbled the title of the thread too, I meant to write "fact or fiction"... Maybe a Freudian slip, eh? ]

 

[83bj60]

Sorry for the hijack, folks, but what's the point of replacing just a small fraction of the tranny fluid ( a few quarts) when the whole system takes something like 3 gallons? Gray, could you elaborate on the technique you use? I read somewhere you could disconnect a hose, let the engine run, and add fresh fluid as the old stuff would come out of the hose... Does that sound right? I'm a complete newbie when it comes to auto transmissions, any advice would be greatly appreciated!

Thanks for your input and sorry again if it causes interference...

 

[-Spike-]

You have to trust the dipstick. You have no choice. If it were wrong it would be an easy recall for Toyota. It's there for a reason, it gives you the actual level of fluid rather than guessing how much you took out and how much it holds and how much it might have been low, etc. I would trust a dipstick over a printed guide and guesswork every time.

I have also heard it's bad news to overfill a tranny. Serious bad news. I don't know how much overfill is enough to cause problems though. It would be serious bad news to overfill your engine oil by a gallon- the pistons would be slapping into it on every revolution, that wouldn't be good at higher RPM ranges, not to mention foaming. I don't remember the possible ramifications of overfilling the tranny, but when the guy (whoever I talked about it with, don't remember him either ) suggested some I said 'OK then, I'll keep it at the right level'. I doubt if a quart over or under on the tranny would cause damage, but the dipstick and procedures are there for a reason. Easy enough to get it close.

-Spike

 

[-Spike-]

Sorry for the hijack, folks, but what's the point of replacing just a small fraction of the tranny fluid ( a few quarts) when the whole system takes something like 3 gallons?

A popular method for maintenance on the tranny is to pull the tranny pan drain plug when changing the engine oil. If you do this at every oil change you are 'refreshing' the fluid and getting some of the crap out. Better than doing nothing, argueably better than changing all the fluid at long intervals- and definitely easier.

You can do something similar with the power steering fluid (for which Toyota specifies tranny fluid, coincidentally) with a turkey baster or vaccuum pump. Empty the reservoir and refill. It's not a 'flush', but do it enough times and you'll have changed the majority of the fluid and pulled a lot of crap out.

-Spike

 

[e9999]

the one scary thing about the disptick, though, Spike, is that for all you know you may have a Toyota T100 dip in your truck (or worse, a Heep one... yuck! )

that would suggest that the FSM figure is a better way to go, cuz what are the chances of a typo in a FSM after all for something so potentially crucial? If one were really convinced that overfilling is so bad, one would have to go with the FSM figure instead of the dipstick...

 

[gray]

the one scary thing about the disptick, though, Spike, is that for all you know you may have a Toyota T100 dip in your truck (or worse, a Heep one... yuck! )

that would suggest that the FSM figure is a better way to go, cuz what are the chances of a typo in a FSM after all for something so potentially crucial? If one were really convinced that overfilling is so bad, one would have to go with the FSM figure instead of the dipstick...

X2 on Spikes comments:

Regarding the dipstick length; if for some reason anyone thinks they got the wrong dipstick in their cruiser; just check against the length of their neighbors or, just order a new one.

Story follows about dipstick length:

I once got a buttoned-up A440F tranny-transfer case combo for my 62 from Spector; he goes to Japan, fills up shipping containers, and brings the parts back to the US.

I had it installed by a Toyota dealer. When they were done they noticed that the old dipstick would not fit into the replacement tranny, assumed there was something wrong with my old dipstick, and ordered a new one.

But gee, the new one didn't fit either. So, as I recall, they clipped
the dipstick to make it fit, really.

When I came to pick the vehicle up, I took one look at the tranny, and saw that it had a different tranny oil pan (shallower) than my US spec A440F. This tranny had been dropped shipped directly to the dealer, so I never saw it before the install.

It apparently was off a different non-USA spec LC, and had a different pan, which was actually not as deep as our pans.

Point of the story; check your dipstick (length) if you think it is wrong,
(and pan if you think it has been changed) but go by the dipstick; that is what it is there for.

g

 

[latinoguy]

I had the same thoughts when I doing a drain and refill. I have done it twice now and feel that the FSM is wrong, if you just refill 2.something quarts....That means that there is more than one driver whose tranny dip stick reads low if you follow the FSM....That is no coincidence.... I put around 3 quarts of ATF back in....
but I am dissapointed the FSM is potentially OFF in such a critical measurement....

 

[gray]

Sorry for the hijack, folks, but what's the point of replacing just a small fraction of the tranny fluid ( a few quarts) when the whole system takes something like 3 gallons? Gray, could you elaborate on the technique you use? I read somewhere you could disconnect a hose, let the engine run, and add fresh fluid as the old stuff would come out of the hose... Does that sound right? I'm a complete newbie when it comes to auto transmissions, any advice would be greatly appreciated!

Thanks for your input and sorry again if it causes interference...

83bj60:
As spike says, if you were to change out a few quarts of ATF at
every oil fill, you would be ahead of the game, and within 6 changes
you would have pretty much changed out all the ATF. Of course
the stuff you added a year ago, is now a year old, etc,etc,etc.
But much better than trying to get 100K out of regular ATF and
then only flushing it once, I think.

Depends who does your oil changes also; if you do it yourself, cheap,
if you pay someone to do it, not so cheap (to drain and fill the ATF at
every oil change).

I do not flush my own tranny; have a guy do it who has a BG shop,
and I use Mobil 1 Synthetic ATF which lasts much longer and holds
up to heat much much better than some bulk brand of ATF you might
find at a Quick lube shop. Some of these shops will allow you to bring
in your own ATF, or, shop around for one that carries what you want
to use.

Some guys have done it themselves, but frankly; it is not worth
the hassle and mess if a comes loose and sprays your driveway and engine with few quarts of ATF.

For that job I pay someone else to get dirty. But you have to ask a few questions;
the most important is to use a machine that uses the trannys own pump
to flush the ATF through(most do), and to use at least 12 quarts; I used 16, I also
used two bottles of the LUBEGARD tranny flush before the flush; seemed to work well, for me. (NAPA and Advance Auto carries it).


g

 

[83bj60]

OK then, it would seem the best bet is to have it done... Just that I prefer to do it myself to LEARN how it's done (I can always get it done in a shop afterwards)

Anyway I thought it was a 'simple' matter of disconnecting a hose, run the engine and let the tranny flush the old through that hose as you fill it with new fluid...

Thanks for your imput, gray, much appreciated

 

[sseaman]

i thought i had read somewhere to replace exactly what uo take out, this is how ive done it and the dip stick looks right on when i get done. No special equipment just an extra quart bottle to start with

 

[CJF]

OK then, it would seem the best bet is to have it done... Just that I prefer to do it myself to LEARN how it's done (I can always get it done in a shop afterwards)

Anyway I thought it was a 'simple' matter of disconnecting a hose, run the engine and let the tranny flush the old through that hose as you fill it with new fluid...

Thanks for your imput, gray, much appreciated

Plenty of folks here change out (passive flush) the tranny fluid themselves; pretty sure there's a write-up in the FAQ. And plenty of folks (me included) would NOT trust a shop to do it.

Curtis

 

[CJF]

For that job I pay someone else to get dirty. But you have to ask a few questions;
the most important is to use a machine that uses the trannys own pump
to flush the ATF through

Agreed. Definite consensus around here that you do NOT want an "active flush" in which some pump other than the tranny's own is being used.