2019 Tundra Tranny Temps 225-235F

What were you hoping to get to?

 

When towing flat under 200f but maybe that was expecting too much.

 

Is this an app or ultra gauge/scan gauge to monitor the temps?

 

It's the OBD Fusion app connected to reader plugged into the OBD port.

 

With the transmission thermostat closing at, say 190 deg (wag), and opening at, say 220 (wag), and the ATF still being "warmed" by coolant at 190-200 deg, don't expect any huge variations in fluid temp. The only way to get 40-50 degrees lower steady-state ATF temp is to pin the thermostat open, which defeats the purpose of the thermostat. I would expect your future ATF temps when towing to remain fairly constant and under a very acceptable 210 degrees.

 

Just put in top of line trans cooler easy install did on a BMW X5 2010 same I believe ZF 6 speed Transmission! Find local transmission shop to do it! Ask there advice!

 

You guys have me worried now since I tow a small trailer to the desert. I have a 2013 CM 4x4. Does anyone know if I would have a tranny cooler? I am at work so I can't check at the moment.

 

All trucks with the towing package had a cooler before 2019.

 

I surprised at your trans pan temps being that high with cooler. Ever since I put cooler on cant get above 200F, usually hang around 195F. 5Klb boat, high 70's on outside air temp. On flip side imagine without the cooler you would be 250F? maybe higher. Once your above 190F and cooler thermostat fully open don't think pinning it open would help much. Sure couldn't hurt might be a good test. Pressure drop across thermostat can't be much.


Make sure you don't have a crushed hose up by cooler restricting flow.

Trailer brake dragging load is 87% is that normal when towing your boat?

 

He clearly doesn't have the thermostat pinned, and the thermostat is not staying open all the time. The thermostat is opening and closing like it should to maintain the set temperature. He's needlessly concerned that Toyota has the thermostat set temp slightly higher than coolant temp.

 

Thanks!

 

No once the thermostat opens at 190F it doesn't fully close until 175F? The thermostat isn't a snap valves the closes instantly at it set point. Most wax type thermostats open at set point but are not fully closed until 10F-15F below. So if he is at 210F on pan temp he thermostat is 100% open all the time. If thermostat is 100% open then how would pinning it open help? May take longer to get to 210F but it will and once it does having the thermostat pinned won't help.

 

Yes that is pretty average - the T top acts like a giant parachute.

I'll check the hoses to make sure nothing has gotten pinched.

Last time I made this run, it was 80 out and my pan temps were lower.

 

I could not care less if the "thermostat set temp is slightly higher than coolant temp". I spent $800 on a cooler and expected it to be lower when towing on a flat road when ambient temps are 57F outside pulling in S5 and S4.

 

Sorry, can't help you. The cooler kit is just executing Toyota's design intent on a truck that never had a cooler. Your expectations are contrary to Toyota's design intent. There is no way your ATF temp can be lower than 190-205 degrees (coolant temperature), it's just f'ing impossible...UNLESS you pin the thermostat (NOT Toyota's intent).

 

How come? How is the trans pan temp linked to the coolant temp? Not being a smart ass, just don't know.

Seems like with the cooler being air cooled, would not matter about coolant.

 

Toyota added the so-called "puck" (warmer) many years ago with the goal of quickly raising transmission fluid temperature to near engine coolant temperature for reduced friction inside the transmission to improve fuel efficiency. For those trucks with the tow package, they kept the air-to-ATF cooler up front, but added a thermostat to provide additional fluid cooling only above a certain set point well below the temperature limit for fluid oxidation.

That "warmer" continues to heat the circulating transmission fluid regardless of what the thermostat is doing. There is no control on that warming function, and that does not change even with supplemental cooling up front. The thermostat is designed to allow the heat exchanger to cool the fluid to a set temperature in a narrow range right around design intent (210 degrees? Idk.).

Unless the thermostat function is disabled (pinned open) to allow maximum cooling available from the heat exchanger, you can see that your transmission fluid can NEVER be much below the engine coolant temperature. The supplemental cooling from the heat exchanger has to literally "overwhelm" the warming input from the engine coolant, and that won't happen if it's being thermostatically controlled.

 

Good info, I appreciate it. Perhaps my concern, rather dissatisfaction, with it not being cooler than 210F is unfounded.

It was running 260F and north prior to the cooler so I guess I should be happy.

 

Yes, I think you should be happy. The kit has achieved Toyota's (original) objective. Better than having your transmission fluid temp alarm go off at 302 degrees (Bingo).

 

Puck is pretty small hard to believe it has enough input to drive trans temp with cooler. My engine coolant rarely sees 200F, I in Houston it stays hot in winter and blistering in summer. Cost nothing to check trailer brakes, wheel bearings, hoses. I would have zero concerns at 210F, I have a searay 210 and pull at 70-75mph in Drive. My last truck F250 kept trans fluid pinned at 195F so I sure wouldn't be concerned.

My buddy boat trailer he spent a summer cooking rims (discolored) and tires. repacked/replaced bearing still blistering. Stupid shit didn't realize he pulled the coupler break free cable that actuates the brakes in case of separation. I reset it, bearing and wheels cold. I told him to ck also, cant fix stupid.

 

True. I'm fishing Wednesday and will pull the wheels and hubs then. Pale Horse II is sleeping in her storage stall until then.

Def costs me nothing to check all of that.

 

Curious if the powertrain warranty has been discussed related to the transmission fluid and the potential for future failure. My dealer offered included lifetime powertrain. It appears that it covers the transmission internals. Is it worth weighing the option of just driving and towing with the truck the way the factory made it. If an issue arises send it for warranty repair?
Or have I glanced over the fine print of the stipulation of the warranty?

 

If your dealer is the one that offers it, you would have to read the fine print because most dealers don't do this. You need to find out who is actually providing the warranty, because it's not toyota. If it's the dealership then you might be required to have all services performed there, or some other type of loophole might be written into it. Also, does it have a deductible? Is it transferable? You will have to do your own research because this is something being provided by your dealership and isn't offered everywhere else.

 

Something else to consider regarding the phrase " transmission internals" is does it cover labor as well? I would be very weary about 3rd party warranties, I have heard so many negative stories about them.

 

Same here. I live in the Bay area. I notice the TF1 was about 224-230 F at 80 mph without towing. The TF2 stays around 240 F most of the time and hits 256 for a moment.

 

Just an observation since I have installed an aux cooler and started monitoring temps on my ‘21. Once warmed up, my pan temp stays right around the same temp as my engine coolant (185-190ºF). Pan temp has to go >190ºF, usually 195ºF, before I notice the thermostat opening. While the thermostat is closed, I have observed TC temps peaking in the 220ºF range (sometimes up to 228ºF) before the thermostat opens and the fluid in my aftermarket aux cooler flows back in and cools things down. This is while driving unloaded on very hilly highways in middle Tennessee.

I am also noticing what you said: due to the heat exchange puck, my trans temp will never be much lower than my engine coolant. It seems that it takes a really long time to get the trans fluid up to engine coolant temps, but once it’s there, it stays close. It would be easier to just trust the Toyota engineers if this didn’t seem to fly in the face of most other pre-existing transmission temperature guidelines. I will continue to monitor. I still haven’t towed a single thing with my truck. Haven’t needed to yet. Will probably be towing a boat this summer.

 

I too just install a Scangage. Correct me if I'm wrong but I thought I read somewhere That the Temps the scangage is showing tend to be higher than they actually are. Something to do with where the sensors are located with in the transmission. BTW mine stay in the 195-215 degree range unless I'm really pulling a good grade. No Towing. At This point I have decided to service/flush my trans at he dealer every 30,000 mile or so. I do tow a small camper (2800lbs loaded) during the nicer weather.

 

The accuracy of ScangaugeII fluid temperature readings is not any different from any other device used to read the OBD2 output.

All OBD2 devices are reading the same voltage signals, off the same OBD2 pins, from the same thermocouples mounted in the transmission valve body. There will be some variation of fluid temperature across the transmission, but those thermocouples are located right where Toyota engineers wanted the temperatures measured. Any need for transmission fluid temperature data, i.e. for Techstream diagnosis, high fluid temp alarm, etc., is referenced to those locations.

For fluid temperature monitoring while towing, absolute accuracy is not that critical. Knowing maximum fluid temperature within 10 degrees would be accurate enough to let you know if there's a problem. The higher the maximum fluid temperature, the more critical that 10 degrees would become.

 

Here is a very informative post a little while back from another member that seems to reinforce your thoughts on the degree difference

@jordoncloutier may be able to expound further on the issue

https://www.tundras.com/posts/2056920/

 

Good to know. Thank you