Transmission cooler questions 2021

I’m thinking about adding a transmission cooler to my 2021 Tundra, I have a few questions about the fluid temps and levels after installation. Genuine Cooling Systems is the kit I’m thinking about installing, please mention a better kit if you know of one.

1)At what temperature does the transmission thermostat engage to allow trans fluid to flow to the cooler?

2) Does the thermostat engage between 99* and 111* (fluid level check temp)

3) If it doesn’t engage between these temps, will there be enough fluid in the transmission when the thermostat does engage to composite for the extra volume in the tubes and cooler?

4) If it does engage between these temps, will there be too much fluid in the transmission when the fluid from the cooler flows back the transmission?

I may be overthinking this, thanks for your help

 

1. ~190ºF
2. No.
3. You are supposed to add about a quart and a half of fluid to the transmission after installing the kit, leaving the thermostat pinned, so it can circulate. Then, between 99-111ºF, open the drain plug and let excess flow out to a trickle.
4. Not if you follow the steps properly.

 

^^That ^^


Welcome from NY.

 

thanks for the info!

 

I purchased and installed the Genuine Cooling Systems cooler you are considering and have been happy with it. I thought the transmission cooler thermostat opened at 195, my transmission temp reads 194 most of the time I am driving around. (according to the OBDII reader so it may not be precise) Before I installed it would get up to 215 on the freeway on the way to work unloaded, and as high as 268 while towing my trailer.

 

thanks for your reply! The lack of a trans cooler makes me very nervous, as I use my newly purchased tundra for towing my camper and work trailer. When I found out the later gen2’s didn’t have one. I quickly looked for an aftermarket one to install myself. It’s good to hear other have had success with this kit and I’m looking forward to getting mine installed.

 

Around 180°

No

You pin the thermostat open when doing the level check so that the radiator and lines are full.

No

Dont worry, I researched adding a cooler since I found out mine didnt have one in 2019 and didn't actually bite the bullet and install one til this year. Its a tough decision since its not cheap but definitely makes a huge difference. My temps stay around 185° now. You can't go wrong with the genuine cooling solutions kit, its as OEM as you could possibly get and looks great once its all mounted up, very professional kit.

 

Thanks for your reply, what size cooler did you go with? The 15 or 20?

 

I went with the 20, I figured for the money I'm spending what's another $70. Its probably overkill but at least I know I'm safe to tow what ever size camper I choose. I did some tests without a trailer on a 100° day with the thermostat pinned open and it kept the temps under 180° with the thermostat unpinned it keeps temps around 185°.

 

Mine does not open that early. I monitor engine oil, engine coolant, transmission pan, and TC temps in addition to transmission lockup. Mine is around 190-195 before it circulates in the cold fluid that is trapped outside the thermostat.

Toyota wants it to run hot. It’s meant to be around 190-200. It’s just that without an external cooler, those temps start to run away much higher too easily. I was seeing 225+ at the pan unloaded on the highway.

Sure thing. The other thing is that you’re supposed to level the transmission pan itself when you do the fluid check. I used my jack and stands to level the pan (front to back and side to side).

There have also been reports of 2019-2021 trucks being overfilled from the factory by the same amount that would have filled the radiator and lines running from the thermostat had it been there. It’s important to get the fluid check right.

 

I concur....it opens around 190-ish degrees

before cooler I was 230 in NORMAL driving - no load. Now I'm never over 193.

does that matter? it does to me.

 

Mine opens at 185. That’s where it settles when not driving hard or towing and the hose is warm to the touch. As said above, you have to pin it to get the fluid to circulate in the cooler while checking your ATF, but then unpin it and let it work as designed.

 

A worthy investment .

 

I'm considering a 2020 or 2021 and I feel like adding one of these is a must. Then I watched some YouTube vids and they didn't seem as concerned. I haven't decided whether to add or not if I got late Gen 2. Anyone not running one and feeling confident without it?

 

Who would dare commit such a dastardly deed?!









(tee hee!)

 

So I just ordered a 20-row trans cooler from Genuine! Pretty anxious to receive it. The installation look pretty straightforward. Watched the video on their site last night, I don’t think I’ll have an issue with the install.

 

Installed one this weekend, definitely watch the video as I'm not sure I would have got it installed with just the directions...dealer wanted $500(4 hours @ $125/hr) to install, that's half the price of the kit.

 

The install isn't too bad. I just took my time and followed the directions and I didn't really run into any difficulties. Hardest part was removal and reinstallation of the TRD skid plate, to be honest. Actual installation of the components was pretty straightforward.

 

Here is Patrick's video that most, if not all of us, have used to install our trans coolers. You will be pleased with Nick's kit. He will be able to answer any of your questions. @Genuine Cooling Systems

https://youtu.be/5DLkja6vXvc

 

I was able to install the whole thing without removing my RCI skid. It was a bit tricky working the hard lines into place, but doable. I bet you actually need to take the TRD plate off though. It’s much wider at the front.

 

I'm guessing since the thermostat is mechanical and not electronic and most likely operated by a spring mechanism there's probably some variances between each one which would explain why some people's open in in the 180 range and some people and the 190 range.

 

...and Houston is Africa hot.

 

https://youtu.be/6IUDNMlKW1U

 

About how long did it take to receive your kit?

 

He ships super quick for in stock items. I ordered when it was on back order but once it was in stock I had it in about 3 days.

 

Wow that’s awesome

 

1) The range of opening temp is somewhere around 185-195F. It should be fully open by 195F.
2) I don't think so.
3) and 4) The procedure indicates how this is done. so not a big deal.

 

I added one because I wasn't satisfied with the fact that there is no system in place to keep temps in a specified range. If 285F is the right temp then cool, fine, great, whatever...but what system is in place to keep it there? This is ultimately what bothered me enough to put one on.

Temps can run away from you and your only recourse is to idle the truck. eff that.

I also have a 2021 4runner Limited (A 750F transmission) and it has an old old old school "in tank" transmission cooler in the lower radiator tank (with no thermostat either). It runs around at 165-185 F all the time unless I'm driving extreme grades. Even then it doesn't go over 220F. It is a 5 spd with 3.73 gears and tows an optimistic 5000lbs. It has a cooler. It has something to manage temps. Same WS ATF group iii type oil too boot.

The paradox here though is that the AB60F transmission is a beast. We are 3+ years into this little experiment of cooler-less transmissions and there is a stunning lack of transmission failures 1) in general (typical toyota) and 2) related to temperature.

Somewhere on here is a thread showing a 2019 that had 300K miles and no cooler. I've seen some local 2019s (5-7 field service trucks) that have no cooler and 100k or more on the odometer. Some have had a transmission fluid service, some haven't. None have had a failure and all shift good. And being a field service truck i guarantee that if a light popped up for transmission temp they'd drive right through it. lol.

If you were going to not add one I'd do the following:

Commit to higher frequency fluid services.
Or change to a group iv synthetic fluid and still change the fluid a bit ahead of schedule.
Possibly invest in an upgraded pan with higher capacity and cooling fins.

 

I followed a similar logic, also coming from a 4Runner.

There was one guy whose transmission burnt up hauling a 3-5k lb trailer. But he ghosted the forum. I still wouldn't expect to see any yet. How many 2019s are out of warranty? It comes with 5 yr/60k miles, I believe. Might be a few that are past 60k miles. If that's all I was going to keep my truck for, I would've saved the $700. Like you said, this transmission is tough. I just wanted mine to operate as originally designed because I plan to keep this truck for a long time.

Also a pan with fins wouldn't do me much good as I am covered up by a cat protection plate.

 

Makes perfect sense. Thanks for the detailed response!