Let’s talk about transmission coolers

Got a 2015 SR5 with oversized tires, camper shell, and off-road bumper and winch, so i have a little extra weight, but no towing package (no trans cooler?). Plan on towing a boat (4k lbs give or take) to the coast 3-4 times per year, about a 5 hour/250 mile tow. I regularly pull a 30hp tractor as well just not long distances. I have an aftermarket trailer brake controller so stopping isn’t an issue, but I’d like to keep my transmission healthy for years to come.
Did the 2015s SR5s without a towing package come with a trans cooler? Who all has added one? Do I even need one?
I’m in Alabama and it stays 100+ degrees in the dog days of summer, so the cooling capacity of most vehicles gets tested. Any info would be great, and real life experiences would be even better.
Edit 1: From a little research i guess all 2014-2019 5.7 tundras have radiator trans coolers. Crawled under the truck, I have the factory trans cooler that uses the bottom section of the radiator as a cooler, as well as the trans thermostat and hard lines. Im sure this helps a lot, but I’m going to hook up to my boat and tow it in a hilly area for about 45 minutes and see what my temps look like. Sadly it’s not very warm yet so this won’t be a great test. Still, I’d hate to make it halfway to the beach and have issues. Would be an easy way to ruin a great trip

 

Do you have a gauge to tell you what the temperature is at?

 

I don't think this has been discussed before.

 

At least I didn’t ask about a leveling kit, tires, oil weight, or blinker fluid levels.

 

No gauges for me. Debating on getting a new Scangauge 3 for trans temp and Speedo correction

 

My '15 with tow pkg (cooler via A/C) can easily get over 240 in any outdoor temp (yeah even in freezing CO snowstorms), I can only imagine what it would do towing. I'd add a cooler even if it already has one. I added a hayden 699 (won't start passing fluid until it hits 165) and all is good. Luck.

 

"....but will this fit?"

 

If towing you'll want a cooler. @Genuine Cooling Systems sells one made of mostly OEM parts.

The other option is to change the fluid out at a more frequent interval.

 

I went with @Genuine Cooling Systems on my ‘21 [no cooler] and I don’t tow that much. Maybe it will help my transmission last longer. My trans temps got up to 235° in the Smoky Mountains pre-cooler.

 

Looks like the nicest kit you could buy, but I can’t see spending $1,200+ dollars on a cooler. I guess it’s time to hit the junkyard

 

Added one to my 21…they sometimes offer a Tundras.com discount thru genuine cooling systems. That’s the kit I have, there’s videos on line to do it yourself.

 

Not familiar with the 15’s, but if they have the S option on the tranny, there is a decent chance S4 will keep your temps tolerable. I’d be testing it with the scan gauge or the like to see if temps are an issue towing and go from there. My 19 has possibly the weakest cooler known to exist, but that puck does fine with the tranny in S4, but I also have the tow haul button engaged too. I tow a 4,000 boat. Good luck.

 

A toasted trans I guarantee will cost more lol

 

Its not all that much when you think about it. You're getting the OEM thermostat, OEM hardlines, OEM hoses, OEM ATF fluid, custom made mounting bracket, Setrab radiator, connections and hoses. Its not cheap but neither are these transmissions. If you're going to hit the junkyard you will need to grab the thermostat, hardlines and hoses and fab up your own bracket and get a radiator. Having the OEM thermostat, hardlines and hoses is the biggest thing, what you use for a radiator probably wont have much if an impact.

 

So I crawled under my truck a few minutes ago and it looks like I have the thermostat and hardliners. From the research I’ve done all these trucks (2014-2019) came with a radiator with a core at the bottom reserved just for transmission fluid. Aka- the lower radiator section is the trans cooler. I’m sure this is much better than not having a trans cooler, but not as good as a stand-alone unit. Anyone ever converted over to a standalone unit? From the looks of the install videos on the genuinecoolingsystems.com videos, all I might need is a separate radiator/cooler and some new soft lines. I’m going to get a Scangauge and haul my boat around a hilly area close to me first and see what my transmission temps look like after about 45 minutes.

 

What kind of boat are you towing? I know 4k isn’t much but my boat is a center console with a ttop. Around the 60 mph mark it feels like the boat is pulling against you on the highway

 

Weldcraft 188 with steel ez loader trailer. Boat is 18’8” plus a 2’ motor pod on the back. Often tow it with the full top up. Has a 140 Suzuki and 9.9 Yamaha. So it’s loaded down pretty well. I sure know it’s there, mostly on bumps, may be too heavy on the tongue weight. Once at speed on a level freeway, don’t notice it much unless I change lanes or go uphill. Also tow a 18’ drift boat, aluminum trailer, around 1,250 pounds. Really catches air so costs mpg almost the same as the heavier boat, but tows noticeably easier.

 

What you have is actually all Toyota ever had for transmission coolers on the Tundra in the second gen. First gen was the only one that had an actual standalone cooler. I would get a tool like the OBDlink MX+ and monitor your temps first. With a standalone cooler without towing you should be able to maintain around 189 in the pan. You can absolutely easily do an add-on cooler since you already have the lines running up front, @Genuine Cooling Systems used to offer add on kits but I haven't seen them offered since he re-did his website.

 

I’ve got an 18’ Cape Horn with a single 115. It’s not fancy but it’s deff a fishing machine. I’m pretty sure I’m a little heavy on the tongue as well, but I haven’t towed it with the tundra very much so we’ll see how it handles

 

From researching that’s what I gathered. I know everyone gets mad at people for asking what seems like generic questions, but you find a TON of misinformation online, and you can easily get lost in all the “knowledge” on a forum. One of the higher rated YouTube videos a guy is talking about the trans cooler but has pictures and video of his power steering cooler lines.

 

Am sure it will handle towing the weight just fine. Probably squat some and may run hot in the tranny.

 

LOL