Adding 2nd trans cooler

Has anyone else added a 2nd trans cooler to a truck with an OEM cooler ? I have a 2016 with the thermostat pinned and was seeing converter temps as high as 255 and pan temps around 230 towing in the mountains. I had planned on adding the hayden cooler and running it through that one first as it has an internal thermostat to allow temps to be somewhat normal until it’s really needed then off to the oem cooler . Thoughts ?

 

Interested in this as well or if anybody knows a larger transmission radiator/cooler that would replace factory one in a a plug and play fashion?

 

When you got these high temps in the mountains, what were you doing? Were you in 4Hi? 4Lo? Speed of travel? Going up or down hills? Dirt or pavement? How many miles on the truck? Has the transmission ever been serviced?

Lots of missing info that needs to be filled in before I'd spring for a second cooler.

A common issue that heats things up super fast is people using 4Hi and driving slow on off road trails/rough roads, especially uphill. If you were doing this, you probably don't need a new cooler, you just need to use 4Lo at speeds sub 20 MPH as it will lock the converter up and keep it from building so much heat.

If that's not what you were doing, details on what you were doing may help with solutions.

 

truck has 117k trans serviced 1k miles ago . Just in 2WD pulling steep grades maybe 50 mph . Rpms are to low to hold speed in 4th so I have to be in 3rd unlocked converter just builds heat super fast.

 

I was going to use the Hayden 699 cooler - I would say it’s pretty plug and play especially if you just bypass the old cooler - just make your own mounts

 

50 MPH, even on a steep grade, should have plenty of airflow for a truck equipped with any kind of transmission cooler. I'd be checking what is currently installed to see if its fins are damaged or clogged, or possibly if there is corrosion in the cooler that is preventing flow. Just my opinion.

 

Good thought! I didn't even think about the fan possibly struggling.

 

my last 2016 tundra did the same thing. These long mountain passes in AZ are tough. Should I be less focused on the converter temp?

 

Pan temp is the important one. The converter will always get quite a bit hotter than the pan, but it will also cool so long as the pan temps are down. How much are you towing? Are you in tow haul mode for the pull? Are you using cruise control? IIRC using cruise will disable certain behaviors of tow haul mode, so you shouldn't be using both in hilly terrain. @ColoradoTJ correct me on that if I'm mistaken, please.

We have 6-8% grades all over and I've towed some and never felt the Tundra was heating up excessively, but I also towed infrequently enough that I didn't have a way to read the temps.

 

Right, but that's also what is going to cool the converter, yes?

 

Correct. Pay more attention to pan temperature. TC temp is more to show that the TC is locked or unlocked.

 

Windshield washer kits are under $20 on Amazon. Install one, only use a nozzle that sprays, not streams. Evaporating water will keep anything from overheating. Engine will also benefit from extra cooling in mountains.

 

Interesting idea you have there. It surely would work.

 

I'd use distilled water to prevent calcification on the fins....

 

Good point.

 

With a pinned transmission how long till the trans gets to a operating temperature?

 

I get to 180-190 fairly quick

 

so I just have tow haul on . Is s5 or mainly s4 . I don’t wana tow at 75-80 so at 3-4K ish in s3 I chug up the mountains at around 55-60 but the passes are super long so by the time I get to the top my TC is already hot

 

yeah I just wish I could get lock up in 3rd. For me to be at like 4K ish in 4th to hold speed I’m doing 75-80 which I don’t want to tow 7500lbs that fast so I have to be in s3

 

im not to sure , I will say that my previous 2016 tundra same trim level / miles / tire size and everything had the same temps climbing the same hills . I sold my last one for a duramax / sold my trailer / sold the truck then back into a tundra lol

 

You found the yin to your yang.

 

Anyone purchased or considered purchasing a deeper pan with cooling fins? For me keeping my 21 In warmer climates year round it seems like a good idea. Especially the extra capacity. I'm lucky to have a sister that owns a Gen II and has a doctorate in industrial engineering specializing in heat transfer. I may run it up the flagpole and see if she salutes it.

 

Maybe this is interesting to you??

https://sdhqoffroad.com/products/09-21-toyota-tundra-ab60-transmission-hi-tek-trans-pan

 

I level out @165-ish after about 15 minutes.

even with the engine coolant temp hitting 190.

 

It might be worth it to get an HPtuners MPVI2/MPVI3. Buy the tuning credits and you will have full access to tune things like converter lockup and such. Then you can read up on this thread and toy with changes yourself to see what kind of improvements you can make as far as TC lockup in the different gears. The factory tune does not allow 3rd gear lockup unless the coolant temp is over 208, and or the transmission fluid is over 257 if I recall from a post in this thread. You can change that if you feel comfortable as outlined in here.

https://www.tundras.com/threads/instructions-for-custom-tuning-the-truck-with-hptuners.70590/