More Trans. Temp Questions......

Recently installed a TruCool 4544 cooler that has a GVW rating of 22,000 lbs. on our 2016 DC SB V-6 tow package truck. I thought that might be a bit overkill but after some driving I'm not so sure. I plumbed the 4544 in series with the Toyota OEM tow package. I was expecting my trans. temps to easily stay below 200°F but after driving some miles since the installation of the cooler I'm still seeing temps in excess of 200°F empty-not towing. I firmly believe I've installed the 4544 correctly and I topped off the fluid so all should be up to snuff.

I've read here that some of you pin the thermostat. I've yet to do that thinking that the large aftermarket cooler would be sufficient that I wouldn't need any extra help keeping the trans. temp low.

I'm going to be doing some towing this summer. Although the trailer that we're going to be towing is more than 1000 lbs. lighter than what the Taco is certified to pull I'm still a bit concerned that I'm going to see trans. temps higher than I'd like to see.

Have you guys that tow and have gone with additional trans. fluid cooling capacity seen a marked reducing in trans. temps while towing as opposed to before you added you cooler? I may be just worrying for nothing but on the same token the last thing I want to do is over cook the tranny and cause damage.

 

Added an extra cooler to my old tundra and only saw the extreme peak temps be lowered. Without I’d see 225 and after maybe 210 while towing

 

The truck wants to keep the trans fluid hot to minimize parasitic lose and eke out slightly more efficiency. So pinning the t-stat is the only way around that. That being said, idk if it's necessarily worth it

 

I suspect the thermostat isn't opening and your new cooler is not being used. Pin it and see if your temps change.

 

Which temp are you measuring?

 

You won't cook your transmission towing 5K is Death Valley in the summer... without your cooler. People worry way too much.
Do me a favor... do a search for how many cooked transmissions on a 3rd gen.
Now assume 10% tow so that's over a 100K people so far.

Why do you not trust Toyota engineers? They tested. Many many many are over 100K miles with no issues. I towed with mine heavy for over 80K through mountains with no light coming on.

I never even thought twice about it.

 

What your airflow situation across the radiator at those temps? I have a similar sized trans-cooler radiator, albeit a little bigger

$59 Hayden 679 Universal 11” Rapid-Cool Add-On Transmission Cooler to Enhance Cooling (not for direct replacement of the factory unit)

Hayden 679 installed on my 2nd gen as a replacement to my OEM trans cooler and I regularly driving empty/not-towing see 140 *F on the highway, but around town and in stop-go traffic, it will climb over 180*F pretty quickly.

 

With the new cooler being in series with the OEM, the ATF t-stat has to open before you’ll see any benefit from the coolers. The temp at which it’s set to open is pretty high for most of us. Around 205*f for mine. If you pin yours open to test you’ll see the result quickly, maybe more cool than you want.

 

I understand completely what you’re saying, and, if Toyota had put a trans temp gauge in the cluster which always reads normal (like the coolant temp gauge) nobody would see any reason to be concerned (or monkey with it). But, being the kind of curious folk we are, we look for ways to make things better. Dang Scangauge!

 

Or sweat the difference between TF1 and TF2 while we tow up hills.. !@#$ lol..

 

Where is the ATF t-stat out of curiosity?

 

Passengers side of trans. Towards the front. Cylinder looking thing with a button lookin plunger about the same diameter as a pencil eraser

 

Exactly ^^


Gizmo looks like:



Pinned:

 

I am an engineer who designs things with transmissions (All types... auto, manual, hydrostatic) and I have a saying...
"Knowledge is power and ignorance is bliss."
I probably look at things a bit differently than most. For the Tacoma, I know they sell 250K/yr. I know they set the limit on towing at 6.5K. When you are designing something that costs $40K and one will sell every two minutes of every hour of every day, your engineering better damn well be tight. Toyota lives and dies on reputation so to have a transmission that cooks when you tow? On a class leading vehicle? Won't happen because they tested the shit out of it.
And, most importantly, while you may be able to monitor temps in 17 different places, neither you nor I truly KNOW what they mean. What's too high for Toyota? What's the duty cycle at what temp? How long can you run at 230 and how many cycles at that load and temp?

So, people get temps and look to others on the internet for answers, only nobody knows and Toyota nor anyone else (except makers of transmission fluids lol) is going to give you the good, real data. Their endurance curves from the test bench. Their real world data from towing 6.5K at WOT up a 7% grade. Their million cycle shift tests and most importantly, their final analysis of when the oil started to break down. I know this data exists because we do the same tests (different application) ourselves and they are industry standard. However, even though they will not give you that data that you and I crave, they have already given us the results of that data. It's in the owner's manual in your glove box under "Service Intervals."
And, if you really, really want to sleep good at night, google the cost of a 125K extended warranty for a Jeep Glaidator, a Chevy, a Dodge and then a Tacoma. If anyone truly knows it's the warranty guys.
For me, ignorance is bliss.

 

Haha very true. Coming from driving a Westfalia for 12 years where you watched the mirrors to see if you were on fire or not, the Tacoma is pretty boring to drive! I need something to occupy myself and the SGII gives me things to think about..

 

Yeah, well your feet stink, how bout dat!

 

The new cooler stays cold until the TC temp hits about 197°F-200°F. I've stopped abruptly several times to confirm this to be true. At some point the aftermarket cooler is cooling the trans. fluid but I'm not seeing much reduction in fluid temp.

As some of the guys above have said I may well be worrying about something that need not be worried about. I'm going to tow the trailer that I intend to pull periodically first with the thermostat unpinned then I'm going to pin it and see if there is an appreciable difference in the course of towing at highway speeds for extended (minimum of 2 hours) periods. I'm thinking the top temperatures will peek at about the same levels. If I see a huge difference we'll be relating that here.

 

But you had the manual.

Manuals do not get hot.

 

When the light comes on the fluid is toast and you have varnish and scorched fluid deposits throughout the tranny. Get an ultra gauge and you can keep an eye on things and adjust your driving behaviour while wheeling and towing according to what you read.

 

There is no light for a manual transmission fluid.