Trans cooler install and system flush

jmferg

New member
I just want to go over a few things and see what you veterans suggest.
I have the B&M external cooler kit. The only things it is missing is something to plug the radiator after it is bypassed. Do you guys just use a bolt and o-ring incase the rad decides to leak internally?

Also, i am guessing Toyota only on the trans filter?
Silicone or rubber pan gasket?

I have a 2001 Automatic with 140,000 and some pretty dirty fluid

Which fluid is better?
Amsoil Signature Series Multi-Vehicle Synthetic Automatic Transmission Fluid
Or Toyota Type T-III

Thanks I was planning on pulling the pan, changing the filter, and reinstalling the pan. Then add however many quarts came out, add that back through the fill tube. Then once unhooked from the radiator, turn the truck on until is pumps out about two quarts, shut off, add 2 quarts, repeat until I go through about 15 qts


Sent from my iPhone using Tapatalk
 
Register to hide this ad
I just connected the two holes together with one hose. If it leaks then I won't loose all my radiator fluid, but I have a new radiator coming soon. I would suggest running a AT cooler and new radiator together.
 
I just want to go over a few things and see what you veterans suggest.
I have the B&M external cooler kit. The only things it is missing is something to plug the radiator after it is bypassed. Do you guys just use a bolt and o-ring incase the rad decides to leak internally?

Also, i am guessing Toyota only on the trans filter?
Silicone or rubber pan gasket?

I have a 2001 Automatic with 140,000 and some pretty dirty fluid

Which fluid is better?
Amsoil Signature Series Multi-Vehicle Synthetic Automatic Transmission Fluid
Or Toyota Type T-III

Thanks I was planning on pulling the pan, changing the filter, and reinstalling the pan. Then add however many quarts came out, add that back through the fill tube. Then once unhooked from the radiator, turn the truck on until is pumps out about two quarts, shut off, add 2 quarts, repeat until I go through about 15 qts


Sent from my iPhone using Tapatalk

Use some Toyota FIPG for the pan seal and an OEM filter.

The fluid is all personal choice. Some have switched their rigs completely over to synthetic fluids. It's more expensive but it lasts longer. Conventional fluids are fine too. You just have to change them more often. You need a fluid that is compatible with Dextron III like a Dex/Merc.

When you say your fluid is dirty, how dirty is dirty? Do you know anything about the service history of your vehicle? I'll get to the reason why I'm asking these questions in a little bit. There's two schools of thought when servicing your transmission. Some believe in just renewing the amount that's in the pan at a certain interval (Usually every 15-30k. I do mine every 10k), which is around 4-4.5 quarts. This effectively renews around 1/3 of the fluid since the capacity is around 12 quarts. Others will scoff at just a partial renewal (a dilution process) and will only do complete flushes.

Getting back to the questions I asked you. If your fluid is really dirty, I mean black and nasty, you might be running the risk of having a slipping transmission after a full flush. The reason for this is the fluid has most likely gone way past the time it should have been changed. With fluid looking like this, there's a chance your clutches could be worn. This old fluid could very likely have suspended clutch material in it helping keep the transmission working properly. Once you remove all that old fluid and replace with thinner new fluid (lacking the suspended clutch material), the transmission could experience slipping. Also, If you know nothing regarding the service history of your transmission, it's probably safer to do a drain and refill as well.

If you know your trans had been maintained properly in the past with regular fluid changes and your trans is just due for another service with that dirty fluid you mentioned, a complete flush using the technique you're talking about should be fine.

Here's a couple videos that might help you out. With the cooler install, I ran mine in-series but some of the material in the video will still be helpful to you. If you go ahead with the flush, you'll start seeing clean fluid at the 12 quart mark. Good Luck and Happy Wrenching!

<iframe width="560" height="315" src="https://www.youtube.com/embed/2nVbwe2t2T8" frameborder="0" allowfullscreen></iframe>

<iframe width="560" height="315" src="https://www.youtube.com/embed/RumPXivBlk8" frameborder="0" allowfullscreen></iframe>
 
Last edited:
Since I'm about to embark on this as well (as you know since I saw you post on my thread and thx) I did think of one other thing...

If you are going to drop the pan and do full service on the tranny it would be a good time to put in a bung for a tranny temp gauge. Not necessary at all but just would be a good time and they are not that expensive. I'm going to do it...at least get the bung in there and then run the wiring and mount the gauge later. Plus most of the bungs are bolt on with an inner section that threads out which also doubles as a future drain plug.

Not sure how I'll mount it yet and that is a source of endless debate but for me obviously as out of the way as I can but hopefully in a way that will still let it drain most of the fluid in the future. Also, even if I don't have it on the "hot" or "cold" side (as again there is endless discussion about) I figure it will still be better than nothing and provide a baseline of how hot I'm running in different conditions, when towing, etc.

Some guys that REALLY want to get fancy will put the bungs on the output and input lines to see how well their cooler is working. I'm not quite that ambitious.

IMG_3136.jpg
 

Attachments

  • IMG_3136.jpg
    IMG_3136.jpg
    131.7 KB · Views: 518
Last edited:
Don't bypass trans cooling via radiator.

I don't recommend by-passing the radiator, if its old, then replace it and run your external cooler in series. With by-passing mine would hit 237 very easily on mild central texas hills, in series it runs under 180 all the time. Luck and enjoy. :cowboy:
 
The Walmart DexIII is perfectly fine for doing a drain and fill. Do it as often as you like to clear things up. I've done it once a week. With a drain plug it's easy. Only 4qts come out of mine.


Sent from my iPhone using Tapatalk
 
I don't recommend by-passing the radiator, if its old, then replace it and run your external cooler in series. With by-passing mine would hit 237 very easily on mild central texas hills, in series it runs under 180 all the time. Luck and enjoy. :cowboy:

Agree. I mean it's more money but if you're going to the trouble it just seems worth doing the whole radiator at the same time if you have any kind of decent mileage on the original. And then running in series with the cooler.

Now, what radiator to get...?
 
I don't recommend by-passing the radiator, if its old, then replace it and run your external cooler in series. With by-passing mine would hit 237 very easily on mild central texas hills, in series it runs under 180 all the time. Luck and enjoy. :cowboy:


The radiator was replaced 2000 miles ago. Are you saying running a stand alone cooler will actually work less efficiently? I plan on adding an e-fan and monitoring the temp and running it from a switch when necessary.
I have a scan Gauge Which never sees over 170, currently averages 130 here during 50 degree weather.
Wouldn't adding a cooler inline, increase stress on the transmission by increasing the amount of fluid and the total distance?

Since I'm about to embark on this as well (as you know since I saw you post on my thread and thx) I did think of one other thing...

If you are going to drop the pan and do full service on the tranny it would be a good time to put in a bung for a tranny temp gauge. Not necessary at all but just would be a good time and they are not that expensive. I'm going to do it...at least get the bung in there and then run the wiring and mount the gauge later. Plus most of the bungs are bolt on with an inner section that threads out which also doubles as a future drain plug.

Not sure how I'll mount it yet and that is a source of endless debate but for me obviously as out of the way as I can but hopefully in a way that will still let it drain most of the fluid in the future. Also, even if I don't have it on the "hot" or "cold" side (as again there is endless discussion about) I figure it will still be better than nothing and provide a baseline of how hot I'm running in different conditions, when towing, etc.

Some guys that REALLY want to get fancy will put the bungs on the output and input lines to see how well their cooler is working. I'm not quite that ambitious.

View attachment 233166

I have a scan gauge to monitor temps. 129.99 and it already saved my engine

Use some Toyota FIPG for the pan seal and an OEM filter.

The fluid is all personal choice. Some have switched their rigs completely over to synthetic fluids. It's more expensive but it lasts longer. Conventional fluids are fine too. You just have to change them more often. You need a fluid that is compatible with Dextron III like a Dex/Merc.

When you say your fluid is dirty, how dirty is dirty? Do you know anything about the service history of your vehicle? I'll get to the reason why I'm asking these questions in a little bit. There's two schools of thought when servicing your transmission. Some believe in just renewing the amount that's in the pan at a certain interval (Usually every 15-30k. I do mine every 10k), which is around 4-4.5 quarts. This effectively renews around 1/3 of the fluid since the capacity is around 12 quarts. Others will scoff at just a partial renewal (a dilution process) and will only do complete flushes.

Getting back to the questions I asked you. If your fluid is really dirty, I mean black and nasty, you might be running the risk of having a slipping transmission after a full flush. The reason for this is the fluid has most likely gone way past the time it should have been changed. With fluid looking like this, there's a chance your clutches could be worn. This old fluid could very likely have suspended clutch material in it helping keep the transmission working properly. Once you remove all that old fluid and replace with thinner new fluid (lacking the suspended clutch material), the transmission could experience slipping. Also, If you know nothing regarding the service history of your transmission, it's probably safer to do a drain and refill as well.

If you know your trans had been maintained properly in the past with regular fluid changes and your trans is just due for another service with that dirty fluid you mentioned, a complete flush using the technique you're talking about should be fine.

Here's a couple videos that might help you out. With the cooler install, I ran mine in-series but some of the material in the video will still be helpful to you. If you go ahead with the flush, you'll start seeing clean fluid at the 12 quart mark. Good Luck and Happy Wrenching!

<iframe width="560" height="315" src="https://www.youtube.com/embed/2nVbwe2t2T8" frameborder="0" allowfullscreen></iframe>

<iframe width="560" height="315" src="https://www.youtube.com/embed/RumPXivBlk8" frameborder="0" allowfullscreen></iframe>


No idea on the trans service history: safer to say it has not been touching. The fluid is dark but not burnt smelling.
I have heard the debate about changing fluid and several schools of thought.
I have been told by several shops that those theories are myths. In my head, dirty fluid has me a little worried because ATF is mainly a detergent and once the old dirty is out, the all new fluid will be begin a massive cleaning of components at once which results to damage to wear components. Are you suggesting a drain a refill maybe every oil change interval then?
Or just a drain and refill once and leave it be.

The Walmart DexIII is perfectly fine for doing a drain and fill. Do it as often as you like to clear things up. I've done it once a week. With a drain plug it's easy. Only 4qts come out of mine.


Sent from my iPhone using Tapatalk



Agree. I mean it's more money but if you're going to the trouble it just seems worth doing the whole radiator at the same time if you have any kind of decent mileage on the original. And then running in series with the cooler.

Now, what radiator to get...?


Rad has been replaced



Sent from my iPhone using Tapatalk
 
Are you saying running a stand alone cooler will actually work less efficiently?

Yes, by-passing the internal trans cooler and using only an external Even with a 3000cfm fan is far less efficient than running in series thru the internal cooler. The reason is external alone is only cooler to air cooling, whereas the internal cooler is cooler to fluid which has far more heat exchange capacity (due to far more molecules to exchange heat compared to air for the same surface area).

I ran mine for a couple years external only and as I said it could easily get to 237 on climbs (probably higher but I would turn OD off and that helps bring it down to 200) but on stop/go in texas 100+ degree weather it would climb to 220.

Once I replace my radiator with a Denso ($95 on amazon free delivery) and the thermostat (found out old one was sticking part way closed) running in series my temps under same conditions above won't go above 180 hill climbing or stop/go, 160 nominal.

So I recommed replacing the thermostat also because when you remove it flushing the block and heater cores (front and rear) is made much easier.

Wouldn't adding a cooler inline, increase stress on the transmission by increasing the amount of fluid and the total distance?

Running in series doesn't increase stress on trans pump but it does increase amount of fluid to cool, lubricate and operate the trans which is all good.

No idea on the trans service history: safer to say it has not been touching. Are you suggesting a drain a refill maybe every oil change interval then?
Or just a drain and refill once and leave it be.

I did a complete flush/filter change out when I got my runner nearly 6 yrs ago. Since then I have done simply drain/fills every 30K miles or so along with using a Magnefine filter attached before the external cooler. So I don't see any issue with all new fluid on an otherwise good tranny.

Luck and enjoy. :cowboy:
 

Attachments

  • Magnefine.jpg
    Magnefine.jpg
    12.3 KB · Views: 351
No idea on the trans service history: safer to say it has not been touching. The fluid is dark but not burnt smelling.
I have heard the debate about changing fluid and several schools of thought.
I have been told by several shops that those theories are myths. In my head, dirty fluid has me a little worried because ATF is mainly a detergent and once the old dirty is out, the all new fluid will be begin a massive cleaning of components at once which results to damage to wear components. Are you suggesting a drain a refill maybe every oil change interval then?
Or just a drain and refill once and leave it be.

Well, I originally thought there was no way it could be bad to renew old ATF fluid but there seems to be enough proof that a worn transmission with old fluid could end up slipping after a full flush. In those circumstances, was the transmission on it's way out anyway? Probably, but it would have lasted longer without slipping if the full flush wasn't done. The shops you've talked to regarding it say it's a myth but you'll probably find other transmission specialty shops that will advice against a full flush with a high mileage transmission with old dirty fluid.

I've recently done research on this and have basically recited some of the things I've learned. When I bought my truck at 111,000 miles, the truck came with service records and the transmission was regularly serviced. I didn't know about the ability to do a DIY full flush at the time so I just did 3 drain and refills over a few thousand miles to get the fluid in good shape.

If you knew the service history of the vehicle and saw that the trans fluid was at least changed a few times, I'd say go with the full flush. Since you know nothing regarding the service history, the safer bet is to start with a drain and refill of the pan. I'd wait another 10,000 miles and do another drain and refill. This is what I do with my rig. By doing a drain and refill of the pan every 10,000 miles, you will have run 12 quarts of new fluid through the system over 30,000 miles and the system capacity of our rigs is around 12 quarts. Most shops recommend a trans flush every 30,000 miles unless you are running synthetic. The drain and refill is a dilution process (mixing old fluid with new fluid) but it does work to keep your ATF in decent shape and is less involved than doing a full flush.

But, do some more research and talk with some transmission shops and see what they tell you. I'd like to know their opinion as well.
 
Reviving this, with just a pan drop, what fluid should I get that will be compatible with the original in it?


Sent from my iPhone using Tapatalk
 
Reviving this, with just a pan drop, what fluid should I get that will be compatible with the original in it?


Sent from my iPhone using Tapatalk
 
Reviving this, with just a pan drop, what fluid should I get that will be compatible with the original in it?


Sent from my iPhone using Tapatalk

Anything that is marked ok for Toyotas is fine. There's multiple kinds you can use, I just put this in:

https://www.walmart.com/ip/Valvolin...utomatic-Transmission-Fluid-1-Gallon/15125768

I use AMSOIL motor oil, but I can't justify using their transmission fluid, it's just so expensive. I picked up 2 gallons (was doing some transmission work so most the fluid came out) of the Valvoline and put it in and runs just fine, plus it's fully synthetic fluid.

I had cheapo bargain fluid in there before and it didn't last very long, only about 30k miles.
 
Anything that is marked ok for Toyotas is fine. There's multiple kinds you can use, I just put this in:



https://www.walmart.com/ip/Valvolin...utomatic-Transmission-Fluid-1-Gallon/15125768



I use AMSOIL motor oil, but I can't justify using their transmission fluid, it's just so expensive. I picked up 2 gallons (was doing some transmission work so most the fluid came out) of the Valvoline and put it in and runs just fine, plus it's fully synthetic fluid.



I had cheapo bargain fluid in there before and it didn't last very long, only about 30k miles.



I was reading through old forums where there has been 2 different Toyota fluids that has been discontinued and updated/replaced by Toyota.
You mixed synthetic with the conventional already in it?


Sent from my iPhone using Tapatalk
 
I was reading through old forums where there has been 2 different Toyota fluids that has been discontinued and updated/replaced by Toyota.
You mixed synthetic with the conventional already in it?


Sent from my iPhone using Tapatalk

Yeah, it's ok to mix. For a while some oil companies were marketing synthetic/dino oil blends, they weren't anything special though.
 
I just did a drain a refill.
I got 4 qts out and only 3.5 went back in. Odd
The old was solid black not even brown.
Shifts a little smoother now.
I used Toyota Type-IV


Sent from my iPhone using Tapatalk
 

Members online

No members online now.

Forum statistics

Threads
278,309
Messages
3,554,071
Members
248,016
Latest member
Advally Service

Trending content

Back
Top