Transmission Temp Light While Off-Roading

Hello. I took my 2020 Tundra TRD PRO off-roading. I had it in 4Hi and climbed a hill that ran for about 1/4 mile. It was moderately steep but nothing extreme. It was all dirt and rocks. Some of the rocks were quite large but nothing the truck couldn't clear. It was the first time I had taken the truck off-roading since buying it brand new. I had a total of 4 passengers with me and an ice chest. About 3/4 of the way up the transmission temp light turned on. We made it to the top and I shut the truck off for about 20min. When I turned it back on the light was off. Is this normal? I hope not. I was wondering if maybe I should have used 4Lo. Should I have the dealer take a look at it? Thanks.

 

The fact that you were on hill might have played a part in what happened because of fluid being out of place due to the slope, but I don't know if it would be the entire cause, more like a contributing factor. That being said, I would have been in 4lo and I would also be promtly changing the fluid after finishing up with a cooler installation.

 

Rule of thumb: if the trail dictates you going less than 15mph go in 4Lo, any faster then 4Hi or even 2wd. Also, I believe your year does not have the transmission cooler like the older ones do.

 

If I need 4WD 95% of the time 4 low is the correct choice. As stated above, no need for 4 high unless you’re running high speed. Your transmission will appreciate the mechanical advantage and hopefully keep the temp from spiking.

 

Thanks for the prompt replies, everybody. I was traveling about 5mph and sometimes even slower due to the large rocks. I will use 4Lo next time for sure. Also, I will look into getting a transmission cooler, too.

 

Might wanna think really hard about changing the fluid promptly, it loses it's mojo after getting too hot.

 

We’re you in 1st the whole time?

1st gear has practically no torque converter lock up programmed on it.

 

Also learn to engine brake. When descending go in 4Lo and into manual mode and down shift. You should barely be on the brakes.

 

I will talk to my dealer about changing the fluid. Thank you for that information.

 

Question, I agree with the 4 low selection but would it help to have had the truck in tow haul mode also ? I run my Dodge work truck, when needed, in 4 high with the tow haul mode on and the tranny seems to shift "when needed" vs 4 low no tow mode. I have not had the chance to off road my Tundra yet.

 

I just had it in 4Hi and drive so I don't know which gear it was in but I was going less no more than 10 mph up the first half and no more than 5mph up the second half.

 

I think it would be a bit over responsive and jerk a bit.

 

By manual mode are you referring to the S next to the D on the shifter? When I downshift will it stay in that gear?

 

Going slow in 4 hi will overheat the trucks that have transmission coolers, too. You need to run it in 4 Lo for the slow stuff.

S mode restricts the truck to the gear you select or lower. Example: You put it in S3 and your truck will not shift above 3rd gear, but will operate gears 1-3 as normal.

Using tow/haul as suggested makes the truck hold gears longer and increases throttle sensitivity. I would recommend against it because of the sensitivity increase as having a touchy throttle on sketchy crawls can end badly. To each their own.

 

Thank you!!

 

True, a long distance at a slow speed in 4h and extreme conditions can overheat the transmission with a cooler due to lack of airflow over the heat exchanger, but it will take a bit longer than if you don't add the cooler.

 

Yes, but I was just trying to convey that the proper way to do a long crawl at slow speeds is 4 Lo with or without a cooler.

 

Well OP, seems to me you are well on your way to a better experience next time around.
Enjoy the truck, and happy trails!