2019 4Runner
1,100 miles on it (basically new)
Stock tires & rims (for now)
No skids or bumpers (for now)
Supercharger & Borla exhaust
No other mods which effect engine or weight.
Have Alpine 309 and was monitoring tranny temps

On flat streets/highway temps run around 150-170.

I was going up to Big Bear Lake this weekend. Paved two lane road with speeds between 35 - 65 MPH with a slow incline (probably around 4K elevation gain over 45 minutes). Temps outside started at 80 on bottom of hill and were are 65 at top.

I wasn't gunning it and tranny operated normal (no lag)

Tranny temps gradually increased... I was in 2Hi driving in auto. Tranny temps grew to 200F within the first 10 minutes and slowly climbed to 233F. Luckily I got to the top of the mountain at that time but I think tranny temps would have kept climbing.

Trying to determine:

#1. What is normal operating temps for 4Runner (assuming around 150 - 175?)

#2. What is max to pull over without causing long term damage? (My tranny temp or check engine light did not go on)

#3. Is this normal issues?

#4. Any tranny cooler write-ups? Couldn't find any...

Mine in LA runs 150 to 170f average. Does get similar temps to you going up the el tejon pass if i run it in D. I now drop it to s4 for long uphills and only reach 190.

The temp warning should go off at 250f at the torque converter. Once it reaches that then yea pull over! Any lower, youre just reducing the life of the oil (anove 200f)

What the other guy said. You should be driving in S4 (or lower) when in mountains, it will be easier for the engine and torque converter to work with higher engine RPM's.

OP, to answer your question, there is no magic number.. even the Toyota service book is vague in terms of when you need to change the trans fluid

Winters I get around 180f. Offroad or hilly spots, it stays close to 195f

Summer time, I typically see figures in the 190s for everyday driving (extremely hot, flat, and traffic). We don't offroad in the extreme summer heat, but some 4wd action on sand easily pushes 220f - 235f within a few mins.

Since my truck is lifted, tires, steel bumper, roof tray...etc. + I depend on this rig as an overland/offroad truck, I'll be changing trans fluid at ~75k miles/ 120k km on the odo just to be safe.

If you drop down into S4 your temps will drop back down into the 190-200F range

everything you described sounds normal, those temps over a short period of time won't hurt anything, 233F is just a little outside of optimal range, but if you try to avoid temps over 200F or maybe 220F max you'll help prolong the life of your transmission

Just a thought... It's possible that the intercooler for your supercharger, which I believe is placed in front of the radiator, is partly restricting air flow across the radiator, which in turn could be causing your transmission temps to rise faster under hilly driving conditions.

Just for a bit of info - the transmission fluid is cooled by the engine coolant. So you should generally not expect the inlet temp to be much lower than the engine temp. In normal driving I think 180 would be pretty common. I think I remember somewhere that 176*f was a target temp for the A750f after a load test - but I can't remember if that was for the pre WS version or the post WS version. Not sure it really matters, just a reference point. Jumping up to 230 would not concern me at all. I'd start to think about backing off at 275 or higher. 302*f is when the warning light comes on.

I towed a car a couple of weeks ago and saw ~225F in pan and ~250F at torque converter on the same grade. I have done this several times and never had the transmission light turn on. S3 and S4.

A little off topic but still related to this topic:

what is the better place to monitor tranny temps, tq or pan?

I think my scan gauge allows me to do both, but not so sure which one is more important.

Currently I'm averaging 180 to 200 in mixed daily driving in socal.


thanks

Hmm odd mine has always gone off (only 3 times actually) at 250f at the tq but it stayed at 250 for a few mins till it did. Pan temps were around 240ish at the time

I don't think I have seen 240 at the pan. I have seen 250 at the torque converter a few times. I am at 59k miles and need to do a flush.