Worried about transmission temps

My wife and I hauled our dinky 16' aluminum fishing boat 135 miles to a mountain lake in western VA this weekend (and back). We have a '21 SR5 with 4,100 miles. Boat and trailer weigh ~1,200-1,300 lbs. loaded.

I babied it the whole way out, shifting between S4 & S5 when conditions required/allowed, and managed to get just over 19 mpg each way. On the very last leg of the journey to our cabin on Thursday we scaled a mountain. Measuring on Google Earth, we went from 1622 ft to 2931 ft over 4.12 miles. It was in 3rd gear almost the whole way up (except it shifted to 2nd once), and due to me going ~40 mph, I'd gathered 3 vehicles behind me. I pulled over at an overlook at the top to let them pass, and when stopped, I smelled that stinky chemical burning odor like when we first bought the vehicle and were breaking it in. It was strong, and my wife was worried that "something broke".

I didn't notice any slipping or any transmission issues for the rest of the trip, or the drive back home. I'm inclined to believe it was just residual burnoff since it's still somewhat newer, but it's hard not to think that something got really, really hot and needs to be addressed. I might go ahead and start the gradual transmission fluid replacement process early.

What do you guys think, waste of money or prudent?

Obligatory lake pics

 

Ya you might want to switch up gas stations.

 

I just pulled a boat twice the weight from Wisconsin to southeastern Ohio 667 miles and didn’t notice any issues and had darn good mpg.. my yota has about 9k and still has that same new car odor of burning off manufacturing greases etc when driving and that’s after I scrubbed down the under carriage personally because I was worried that it was something leaking.. must be a new yota thing..

 

So what were the temps that you're worried about?

 

I didn't have trans temps, but just ordered a Scangauge II for future trips.

My worry was that the strong odors produced on its first trip hauling any weight up steeper inclines might be indicative of an issue. But if it's just regular 'ol burnoff I won't worry about changing the trans fluid over the next 5,000 miles.

 

I have a 2021 with about 14,000 miles and it still smells like something is burning if I’m pulling weight or driving it hard. I think it’s normal.

 

I’m not positive but I think there’s a transmission temp warning light. If that didn’t come on, then your probably ok.

 

I'd be really, really surprised if you overheated your transmission towing a load that small.

 

If that temp light come on you’ve already cooked the fluid. I believe the Tacoma is set at 300 degrees which is too hot. Get a device that can read the temps. If it’s too high get a bigger cooler.

 

That is one beautiful lake!

 

I had no idea that there was a a trans. temp. light. It didn't illuminate so I think it's all good. Thank you!

 

Another reason I think you hit a wall, the EGR may have been working over time to cool the combustion chambers.

 

Check the owners manual because I’m not positive about that.

My 12’ Sequoia actually has a trans temp gauge on the instrument cluster. We never tow so I have never experienced an elevated transmission temperature situation.

 

Did a quick Google search and apparently a transmission warning light is a thing. However, reading online if one does get a high transmission temp then a drain and fill is needed asap as the efficiency of the transmission fluid is diminished a large amount. Again this was on another forum and I am surely no expert. But if you got no light you more than likely didn’t heat up the transmission enough to cause an issue (but again I am no expert in the field). Do what you feel is best.

 

At 5,000 miles, your Runner isnt even broke in yet... If you feel like checking, pull the check plug on the tranny pan and take a sample of fluid when the vehicle is at normal operating temp ( you can drive it around for 10-15 minutes easily to accomplish this). If its brown to black in color, get it flushed. if its blood red to brown, a simple drain and fill may be all you need. If its bright red, you are fine. But I doubt you did any damage. If you feel the need to add some additional cooling and a little more capacity ( 1/2-3/4 qt), get an air cooler, run it off of the return line of the radiator cooler and put it in front of the a/c condenser where it will get good air flow. But I think you are ok...

Were you out by Roanoke or further west?

 

If the AT overtemp warning didn't pop up, you're fine.

 

Thank you for the excellent advice, much appreciated. This is the heaviest thing I plan to haul with the 4R for a while, so might hold off on considering a trans cooler for now. Yours and others' replies makes me feel like it's not a big deal.

We were actually north of Roanoke on Lake Moomaw, and stayed in Warm Springs. Beautiful area, lots of rural mountain countryside.

 

I recently installed heat wrap around the transmission lines that run next to the cats. I got the idea from RC Fabrication on Instagram. This is not a replacement for a transmission cooler but I'm sure it will help keep the temperature in check on the very hot days. Here are a few photos:

 

There is, and that was going to be my question.

 

Last time I experienced that was on a new tundra that had a loose sensor that was misting oil in the engine bay. You could smell it but it wasn't smoking or anything

 

Toyota came and hauled it off to the dealership tighten the sensor topped it off with oil and said it was good to go

 

Well damn I’ll have to look at my Tacoma’s cooler lines.

 

Just do this. I will at some point: