Transmission Fluid Change

[giovannie23]

yes that is the way the trans bolts are, so now I just 'drain' from the hose leading to the trans coolers and suck up fresh from the other until it runs fresh and pink. :cowboy:

so the return hose has suction ?
so i can just drop the return hose in a container fill with fresh fluid and it will create a suction

 

[mtbtim]

so the return hose has suction ?
so i can just drop the return hose in a container fill with fresh fluid and it will create a suction

The return hose doesn't have suction. The fluid is moved through the system via the positive pressure of the transmission fluid pump. You drop the return hose into a bucket to drain the fluid out. You fill via the dipstick tube. You start the engine, drain a quart out, stop the engine. Add a quart via the dipstick tube and repeat the process until you've reached at least 12 quarts. The capacity of our automatic transmissions is around 12 quarts. If the fluid still looks a little dirty to you, keep going until it looks like new fluid is coming out of the return line. Check the level and add if necessary to bring the level to the top of the cold level reading. Take it for a drive and get the trans to operating temperature. Recheck the level and make sure you are in the hot range.

What many of us have learned with our rigs is the cold level reading just gets you into the ballpark. Make sure you take it for a decent drive, at least around 10 miles, to get it into the normal operating temperature range. If I remember correctly, the range is somewhere between 155-175. If you have a Scan Gauge or use Torque Pro, there's no guesswork what temp you're at. If you don't, you'll just have to be sure you drove long enough to get the trans temp up there. Now recheck the level and top it off to the upper hot range level on the dipstick.

[MENTION=102606]infamousRNR[/MENTION] and I made a video of this process. Good luck!

 

[JRZEE2000TR4LTD]

so the return hose has suction ?
so i can just drop the return hose in a container fill with fresh fluid and it will create a suction

No there's no suction on the other hose.

 

[giovannie23]

The return hose doesn't have suction. The fluid is moved through the system via the positive pressure of the transmission fluid pump. You drop the return hose into a bucket to drain the fluid out. You fill via the dipstick tube. You start the engine, drain a quart out, stop the engine. Add a quart via the dipstick tube and repeat the process until you've reached at least 12 quarts. The capacity of our automatic transmissions is around 12 quarts. If the fluid still looks a little dirty to you, keep going until it looks like new fluid is coming out of the return line. Check the level and add if necessary to bring the level to the top of the cold level reading. Take it for a drive and get the trans to operating temperature. Recheck the level and make sure you are in the hot range.

What many of us have learned with our rigs is the cold level reading just gets you into the ballpark. Make sure you take it for a decent drive, at least around 10 miles, to get it into the normal operating temperature range. If I remember correctly, the range is somewhere between 155-175. If you have a Scan Gauge or use Torque Pro, there's no guesswork what temp you're at. If you don't, you'll just have to be sure you drove long enough to get the trans temp up there. Now recheck the level and top it off to the upper hot range level on the dipstick.

[MENTION=102606]infamousRNR[/MENTION] and I made a video of this process. Good luck!

thanks for the video
one question, would there be any harm to the transmission running the return line dry while the engine is on?

 

[mtbtim]

thanks for the video
one question, would there be any harm to the transmission running the return line dry while the engine is on?

You want to avoid that because it's not good for the transmission pump. If you remove 1 quart at a time, that won't happen.

 

[reelamin]

No guesses if you are looking for specific info. 1996 I pulled the tranny drain plug and measured the fluid that drained out. 3.5 qts came out of the pan. Hope it helps someone.

 

[mtbtim]

No guesses if you are looking for specific info. 1996 I pulled the tranny drain plug and measured the fluid that drained out. 3.25qt came out of the pan. Hope it helps someone.

I think you are under-filled. Most people get around 4.5 quarts out when doing a drain and refill of the pan.

Are you checking the transmission when it's hot or cold? Many of us have found that having the level at the top of the full mark when cold doesn't correspond to having it within the hot marks when at operating temperature.

I think you're at least a quart low of being at capacity. Are you checking the fluid when on level ground and the engine is running? I'd get the transmission to operating temperature by driving it down the highway around 5 miles out and 5 miles back and then get it onto a level surface and check it right away before the trans starts to cool down. I'm guessing you'll see that you're not in the hot range if you only replaced 3.25 quarts doing a drain and refill.

 

[reelamin]

I think you are under-filled. Most people get around 4.5 quarts out when doing a drain and refill of the pan.

Are you checking the transmission when it's hot or cold? Many of us have found that having the level at the top of the full mark when cold doesn't correspond to having it within the hot marks when at operating temperature.

I think you're at least a quart low of being at capacity. Are you checking the fluid when on level ground and the engine is running? I'd get the transmission to operating temperature by driving it down the highway around 5 miles out and 5 miles back and then get it onto a level surface and check it right away before the trans starts to cool down. I'm guessing you'll see that you're not in the hot range if you only replaced 3.25 quarts doing a drain and refill.

I checked it cold the last few times, with the engine running, and on a flat surface. I am pretty sure it is in the range, but had not heard the two don't correlate (cold v hot on the dip stick). I have to put my bumper back on tomorrow (body lift) and will check it again hot. Thanks for the input...do not want to put bad info out.

Edit: I checked it and I was low according to the stick. Exactly .25 of a quart. Thanks for bringing it up and I edited my original post.

 

[phattyduck]

I think you are under-filled. Most people get around 4.5 quarts out when doing a drain and refill of the pan.

2WD pan is smaller... maybe his truck is 2WD?

-Charlie

 

[Teedeejr]

RED Seal Packing or Permatex Right Stuff

Well, I just did this yesterday along with my mechanic.
I live in a Townhouse with no garage so have absolutely no place at all to do anything more than checking my oil.
Fortunately I know a good mechanic that lets me help him.

Take the drain plug out obviously, drain it when very warm.
Need to unbolt the fill tube which is in 2 pieces, then take out about 20 or so bolts, think they are M6 and need to be torqued back at 65in-lbs I believe so pretty lightly.
Will need to undo your sway bar to move it out of the way of the trans pan.

Check your screen, IF it needs it take it off and clean it with brake clean.
If the screen needs to be cleaned you "may" have problems on the way. Mine was spotless, looked like new.
Check your pan, see what you got on the magnets (hopefully nothing).
Drain out your external cooler if you have one.
Drain your torque converter.
To actually "Flush" most everything out you need to put everything back together. You will the RED seal packing RTV from Toyota or some Permatex Right Stuff.Fill the trasmission back up to full, take off one of the lines leading to the radiator and have something like a gallon milk jug available.
Have one person turn the car over and ATF will fly out of the line into the jug from the Torque converter, only do about 1 quart at a time then shut it off and replace a quart.
Do this probably about 6-8 times I think until you can see new fluid mixed in with the old which can be hard to notice if your old fluid is in good shape like mine was.
There is probably half of the ATF in the Torque converter.

Personally I use nothing but Amsoil ATF, best you can get and works wonders. Redine D4 is also very good. If you use standard ATF make sure it is the right one, what ever Dextron III compatible ATF that floats your boat.
You will need around 14-15 quarts.
Run it through all the gears a couple of times and check your fluid level for the "cold" level.
Takes quite a bit, like running it on the hwy for 30 minutes to get it "hot" especially with synthetic fluid.

I may have missed a couple of things here, I was just helping so might have missed something along the way, wasn't difficult just time consuming.

Checking out my Trans case I noticed an orange rubber seal all the way around the case. Is this what seal packing or Permatex is? I've recently bought my 4Runner and don't have adequate maintenance records, so I'm wondering if that's a standard seal for a Trans flush or something I should worry about.

 

[reelamin]

2WD pan is smaller... maybe his truck is 2WD?

-Charlie

It's a 4WD and I was .25 low. I updated my original post to reflect 3.5 qts. I'm glad he brought I to my attention and I hope it helps someone. I really like facts not guesses on things like this.

 

[thegipper]

In my experience, it takes quite awhile to fully heat up the transmission. I've learned this since installing a tranny temp gauge. I have to drive around in city traffic for at least 20 minutes before it gets to around 160 degrees, maybe even longer. Now I do live in Wisconsin and its been in the 40's (unusually warm winter so far). If I drive on the highway, it takes forever to heat up if at all really (130ish)

 

[T4R2014]

In my experience, it takes quite awhile to fully heat up the transmission. I've learned this since installing a tranny temp gauge. I have to drive around in city traffic for at least 20 minutes before it gets to around 160 degrees, maybe even longer. Now I do live in Wisconsin and its been in the 40's (unusually warm winter so far). If I drive on the highway, it takes forever to heat up if at all really (130ish)

Is your radiator cooler bypassed? I haven't done it for this reason - I think it helps to warm up the fluid faster. I do mostly short trips, and getting it to operating temps quicker is far more important to me.

 

[thegipper]

Stock radiator and cooler, no bypass

New fluid this spring

Sent from my SM-N910V using Tapatalk

 

[phattyduck]

Is your radiator cooler bypassed? I haven't done it for this reason - I think it helps to warm up the fluid faster. I do mostly short trips, and getting it to operating temps quicker is far more important to me.

The bottom of the radiator is quite cold in sub-freezing temps. Its the last place (if at all) where the coolant gets warm. It doesn't help the trans warm up much, if at all...

If you do want to warm it up, it'll have to come from the top radiator hose, or a heat exchanger off the block like the engine oil cooler, etc.

-Charlie

 

[mtbtim]

The bottom of the radiator is quite cold in sub-freezing temps. Its the last place (if at all) where the coolant gets warm. It doesn't help the trans warm up much, if at all...

If you do want to warm it up, it'll have to come from the top radiator hose, or a heat exchanger off the block like the engine oil cooler, etc.

-Charlie

Well, the coolant gets to 190 degree temperature range pretty quick. You're saying the coolant on the bottom part of the radiator is much cooler than where the temperature sensor is up higher on the radiator. Have you taken some type of reading with a thermal imager or infrared thermometer to back up this statement? If so, what is the temperature reading at the bottom of the radiator when the vehicle is at operating temperature?

 

[quicksilvr]

Is your radiator cooler bypassed? I haven't done it for this reason - I think it helps to warm up the fluid faster. I do mostly short trips, and getting it to operating temps quicker is far more important to me.

Stock radiator and cooler, no bypass

New fluid this spring

Sent from my SM-N910V using Tapatalk

The bottom of the radiator is quite cold in sub-freezing temps. Its the last place (if at all) where the coolant gets warm. It doesn't help the trans warm up much, if at all...

If you do want to warm it up, it'll have to come from the top radiator hose, or a heat exchanger off the block like the engine oil cooler, etc.

-Charlie

I've driven many miles observing transmission temps, as shown by a ScanGaugeII, in a factory cooler setup and a bypassed aftermarket cooler setup.

What thegipper is observing is accurate....and many folks incorrectly believe the factory trans cooler in the bottom of the radiator helps heat up the ATF. In reality, it does NOT. The only thing that heats the ATF up is the transmission working hard.

 

[phattyduck]

Well, the coolant gets to 190 degree temperature range pretty quick. You're saying the coolant on the bottom part of the radiator is much cooler than where the temperature sensor is up higher on the radiator. Have you taken some type of reading with a thermal imager or infrared thermometer to back up this statement? If so, what is the temperature reading at the bottom of the radiator when the vehicle is at operating temperature?

No actual data on the 4Runner specifically. No need though... we have a constantly running fan driven off the motor (even if it is 'slow' most of the time).

See info like this: https://forum.miata.net/vb/showthread.php?p=7639291

And then extrapolate to a vehicle where air is constantly forced air over the radiator.

If you really don't believe it, I can probably grab the Flir from work, but it will be hard to get a great image with all the components in the way.

If you engine temp starts rising above its normal value (more than a couple degrees), then the bottom of the radiator is finally approaching engine temperature. That almost never happens in 'normal' use, and even less often in winter.

-Charlie

 

[mtbtim]

I've driven many miles observing transmission temps, as shown by a ScanGaugeII, in a factory cooler setup and a bypassed aftermarket cooler setup.

What thegipper is observing is accurate....and many folks incorrectly believe the factory trans cooler in the bottom of the radiator helps heat up the ATF. In reality, it does NOT. The only thing that heats the ATF up is the transmission working hard.

Very interesting. I think I'm going to have to get out the infrared thermometer on the fire engine and check to see what the temps are on my radiator at different levels.

Now, trans cooler manufacturers specifically state not to bypass your radiator cooler if you live in cold climates. I reckon their engineers have been misinformed that the radiator cooler does nothing to help heat the trans fluid.

In the FAQ on the True Cool website, this following is a question and answer they give on this topic:Frequently Asked Questions | Tru-Cool

Should I disconnect the radiator in-tank oil cooler when I install a Tru-Cool cooler?

Do not disconnect the in-tank oil cooler if you can avoid it. Your in-tank cooler offers additional cooling and helps preheat the transmission. In colder climates the in-tank cooler should never be disconnected from the system.

Even though you state you saw no difference in temps, I find it hard to believe the radiator cooler is having no effect on heating the transmission fluid faster than a bypassed system. If the trans cooler is bathed in the hot coolant, there is going to be some heat transfer via conduction. There's no denying the science behind it.

 

[quicksilvr]

Very interesting. I think I'm going to have to get out the infrared thermometer on the fire engine and check to see what the temps are on my radiator at different levels.

Now, trans cooler manufacturers specifically state not to bypass your radiator cooler if you live in cold climates. I reckon their engineers have been misinformed that the radiator cooler does nothing to help heat the trans fluid.

In the FAQ on the True Cool website, this following is a question and answer they give on this topic:Frequently Asked Questions | Tru-Cool

Should I disconnect the radiator in-tank oil cooler when I install a Tru-Cool cooler?

Do not disconnect the in-tank oil cooler if you can avoid it. Your in-tank cooler offers additional cooling and helps preheat the transmission. In colder climates the in-tank cooler should never be disconnected from the system.

Even though you state you saw no difference in temps, I find it hard to believe the radiator cooler is having no effect on heating the transmission fluid faster than a bypassed system. If the trans cooler is bathed in the hot coolant, there is going to be some heat transfer via conduction. There's no denying the science behind it.

There is one, and only one scenario in which the in-radiator cooler makes a difference in the regard of heating up the ATF (in a good way). That scenario is this:

If you start you truck from cold when it's say, 15 degrees F outside, and you pull out of your driveway and get on some sort of highway within only a block or so, or only a couple minutes....(basically, the transmission only shifts up/down less than 8-10 times), then after about 10-15 minutes of highway driving, the engine has fully warmed up and the thermostat opens up. The radiator starts actually passing warm coolant through the bottom at this point, and the transmission which is probably only at about 100 degrees F at this point, will warm up from the coolant. It will take a while, but the ATF will get up to about 130-140.....where as a bypassed system, the ATF will stay down around 100-115.


Every other scenario I've witnessed (I'm talking serious miles, 20,000+ miles in both setups observing the ATF with a ScanGaugeII), what heats up the transmission is shifting. I can get the ATF up to 150 before the thermostat has even cracked open if I stop and go hard 10 times in a short period when it's cold outside. The radiator has nothing to do with it getting up to 150....just the fact that it's working and creating friction....which equals heat.

You can do what you want, I'm just trying to be helpful and say what I've observed in real life. People always want to say, "well, the engineers this and the engineer's that"....and that's fine. I'm not going to argue...I'm just stating what I see in real life.

Your last sentence, " If the trans cooler is bathed in the hot coolant, there is going to be some heat transfer via conduction. There's no denying the science behind it" is where almost everyone forgets that by the time the coolant is hot in the bottom of the radiator, the truck has already been driving for enough time to get the ATF warm all by itself. Except for the scenario I laid out above.