TRANSMISSION . Transmission coolers for all Toyotas ... Write up with many pictures

Thanks Gearcruncher and everyone for the awesome posts. Yesterday I installed my TruCool LPD4588 as an auxiliary transmission cooler.
I chose this cooler because it has smaller frontal profile than the 4544 but is thicker and has a similar rating. I chose to use some spare 3/4 water hose over my cooler lines for protective sheathing. I elected not to remove the grill for the install. but would have removed the grill if I did this again because of the number of times you need to remove and install the cooler for bending/sizing brackets, painting brackets, sizing hardware etc. I used some small rubber grommets from my local ACE hardware store to insert into the cooler mounts and the cooler end of the brackets as well as some larger bushings for the mounting end of the lower brackets.
I added a 32 ounces of ATF fluid back into the return line and took out 8 ounces of fluid after doing a fluid level check. So it looks like the cooler and lines added about 24ounces. I drove it last night and will tow with it tomorrow, then will decide if I want to unpin the thermostat....

 

Thank you for posting your install .
Looks good and I am sure it's going to help prolong the life of your trans .
I did this write up because Tacoma World didnt really have much on transmission coolers .
Thanks for the help , we now have a darn good write up with all 3 generations of Tacoma,s .
With this being said ...Thanks guys .
Enjoy

 

Hello ! Is it a good idea to pin the thermostat open in a southern climate for a 3rd gen Tacoma in Northern Arkansas so as to keep the trans temp lower ?

 

Anybody running the Tru-Cool 4589? I’m thinking about this one to replace the factory mini want to be. My fat brick truck trans runs way to hot gaining altitude.

 

Are you watching your transmission temps ?
If you are in a southern state , its a great idea to pin the thermostat , however , your transmission will not warm up as quickly as it normally does with the thermostat functioning . Your fuel mileage will decrease for the first 15 minutes of run time .
If you can afford the extra fuel , I say go for it

 

Yes , I have been watching the temps . On days in the mid to upper 90 deg.'s F and higher , I have seen it as high as 215 to 220 under load without towing ,while the torque convertor is unlocked . Once the load is relieved (flat or downhill road) it fairly quickly drops back down to 190 , this is while driving 60 mph . Also driving in S mode limited to 2nd gear on gravel one lane hilly roads (80deg. F.) I see it around 195 to 215 . I have 30 K on it now and will pin it in spring for the summer months from now on . Do you think I should do a couple drain and fills now or in spring ? I should be at 32-33 K by then and would normally do it at 50 K.
Thanks .

 

I beleive Toyota requests the fluid be replaced at 60K under " Normal " conditions in the AC60E transmission series .
I would like to know what Toyota considers normal ??? Does normal conditions include towing heavy loads or offroading in 4 wheel drive low range or heavy stop and go traffic .

Another issue :some 2020 tacomas with the towing package no longer have an aftercooler . According to Mike Squeers , the Ac60 series transmission has been improved to withstand the extra heat ? I have to look into this
Do any of you new owners know if Toyota upgraded their semi synthetic World Standard fluid ?

With the above mentioned , I would change the fluid at 50K

 

I will be getting one of these coolers. My question is - why would there need to be the cold temp bypass in the cooler when there is already a thermostat in the transmission? Wouldn’t that single thermostat do the job? I am in Montana - no pinning the tstat for me. So I think I can get one without the special bypass. Also how much pan cooling is ‘degraded’ by having a skid over the tranny?

 

If you are considering a True Cool cooler , they all come with a bypass . The bypass in the True Cool doesnt open until 180 degrees . If you are going to use one of these True Cool coolers , the fluid bypasses the True Cool until you hit 180 . Once the fluid hits 180 , the bypass in the True Cool cooler opens up and allows fluid to circulate through the aftercooler .
The thermostat on the AC60 series transmission is used to warm the transmission up to save you fuel . If you pin the thermostat , your transmission fluid bypasses the preheating feature .

becuase 99% of transmission cooling is performed at the front of the truck through the radiator and aftercooler ,I dont beleive you would notice any difference with a skid plate . I do not beleive anyone has tested this yet mind you . Are you running a scan guage ?
Run the truck without the skid plate and record the temp
Duplicate the same test drive with the skid plate and record the temp .

 

The paragraph at the top describes the bypass feature of the transmission coolers. The bypass is always open and ready for cold or cool fluid to flow through the larger tubes. When the fluid gets hotter and thinner, it additionally passes through the thinner tubes at a higher rate.

 

A Tru-Cool 4589 (same as B&M cooler) both of which were made by Long Manufacturing in 2017 and prior.
Two bypass channels on the right side, running from bottom to top.

 

Is there a check valve on the line going from the tranny to these coolers that keeps the fluid in the coolers when the engine is turned off?

 

There are anti-drain back valves inside the transmission valve body that prevent transmission fluid from draining out of the cooling lines and back into the pan . When you shut the truck off , the fluid gets locked in the cooling system .
If the anti -drain back valves were not there or if they fail , your torque converter would gravity drain back through the hot cooling line into the transmission pan every time you shut the truck off .
When all the fluid from the torque converter drains into the transmission pan , your transmission at start up would take 5 minutes before it would go into gear and most likely slip for a while as well.

If you ever need to service the transmission cooling lines , the converter will gravity drain all day once you crack the hot cooling line open

If you plan to install a cooler and dont want all your fluid to drain out of the torque converter , pinch the rubber hose on the hot line while you set up your new cooler .
It takes a long long time for your torque converter to gravity drain 7 quarts of fluid through a 5/16 " cooling line

 

Picked up my trailer today and towed it 1hr 50 minutes home and was up hills, down hills and flat roads. My scangauge TFT was fluctuating around 190-215 throughout the drive home. I have a transmission cooler but the factory stock small one. Should I upgrade and if so can I have a secondary one on a switch to turn it on when I need it when towing and switch it off when not towing? Besides TFT what else is on your gauge for towing on your scanguage?

 

A switchable cooler sounds like a plumbing nightmare.

Just replace the factory cooler with a larger aftermarket one. Then, it just works. No switch required.

Adding a temp gauge is not a bad idea either.

 

that’s not a temperature gauge of the picture I posted? Many say to run a large cooler in the winter is bad for the transmission as it takes longer to heat up?

 

I run a temp gauge with the sensor in the fluid path - in your picture, I am not sure where the Scangauge gets its info.

In the winter, my transmission does take a long time to heat up. I am not sure if that is a problem for the transmission or not. I am planning to add a temperature controlled flow valve - it will only open when the fluid temperature is hot.

 

That’s what I meant a temp control valve.

 

That makes sense now.

That is an interesting thought - adding a control valve and second cooler.

I have had good success with my larger, replacement cooler. I have a temp gauge, and always watch the trans temps. The trans can get a little too hot off-road, towing uphill. I stop for a while, and everything cools down.

The trans does stay really cool in the winter. I probably should add the controller.

 

My 4454 should be here in a day or two. I have OBD Fusion to monitor my truck, including the tranny temps. When we are talking temps here in this thread, are we talking pan or converter temps? My truck was reading 216 pan and 196 converter today, which seems high given the ambient and driven conditions.

I guess I'm curious which temp is the one I am wanting to keep an eye on in regards to operating safely. I'm guessing pan, but I've been wrong once before.