On my 2016 Sierra 5.3 6L80 temps never moved. Didn't matter if I was driving hard or towing. My 2017 on the other hand with the same configuration would stay at 210 on the engine temp and 187 on the trans temp until you started driving hard or towing. Then the engine temp would go all the way up to 227 and transmission temp would go up to 205 at the highest. I feel like this was due to the addition of active grill shutters. I could watch the fan command and grill shutters open with my scan tool. The PCM would not command much fan percentage until the temperature got above 225 on the engine side. With my new 2021 LT Trail Boss with 5.3 and 10 speed temperature never moves very much. Normal driving around trans temp is around 140 where as normal driving in the 2017 would be at 187. So far I feel like the 5.3 with the 10 speed is a much better combination and runs much cooler. Future lifter problems with the dynamic fuel management is always a concern though. But at the end of the day they all have problems. You just have to pick what you like and what you're willing to deal with.

I want a new truck so bad. But it seems like no one can build anything good nowadays. Good luck I hope it works out for you. beautiful looking truck

Happened to me last week while wheelin 2 weeks in Tahoe. Ambient Temps were in the low 90s. The transcooler is the culprit. Very small and not very good heat dissipation. Ordered a Trucool transcooler for cheap and gonna install it. Those have solid reviews even with trucks who tow all the time.

I have a 2019 1500 custom 6Cyl and the transmission heats up exactly like yours does without a warning sign on the dash. Mine will then have a hard time shifting into the next gear after 2nd and the RPM goes up to 4-5 before hard shifting into the next. I’ve taken it to the dealer and they can’t figure it out either.

I love my truck. Exactly the same as yours. About a year ago the oil return hose from the coolant popped off. I was so flicking mad. Luckily no damage to the engine coz I stopped it right away. What gets to me is that this should not happen to a year old truck. I had a 2008 4runner for ten years and nothing like this ever happened. So sad. It got fixed and never happened again so far. Now your situation is another fear lingering in the back of my mind. Gonna lose sleep over it now.

Bigger tires put big strain on the drivetrain if you don’t change ring and pinion and add low gear driving that will create heat .

I have a 20 LT Trail Boss with the 10 speed and I too have been seeing some recent findings that have me wondering. Once this next group of monsoons pass and we are back to 100+ temps I am going to do a test and see if mine has issues going up hill with about a 7K trailer. I do not have much for elevation where I am but the heat will play a factor. That being said I have had other vehicles in the past run hotter engine temps at elevation, low gear, slow speeds. The thinner air and less airflow with the tranny working harder add up quickly so slightly above normal OK BUT way over or even overheat is a nogo at this station. my 14 Ford ecotoot always ran at like 205-210 in "normal" conditions and my trail boss is usually 195-200 but again thats normal city driving. Based on what I have seen no matter who makes the truck a bigger trans cooler is a good idea to keep the transmission happy for many miles come.

Had my trail boss in the shop twice for a transmission pump gear bearing failure. 10L80 10 speed apparently are bad about this issue buyer beware

I just bought a 2021 custom trail boss with the 6speed and 5.3 for 46k. I was looking around a little more after my purchase and found a 6.2 with 10 speed for 46k 😪

Bro why use 4lo should stay in 4 hi probably why over heated

I've had a 21 trail boss lt for 1480 miles, and I keep seeing more and more of these videos. Come on chevy :/

Man I'm 2nd guessing getting one of these now

I am having the same problem with my 2020 Trail Boss. I have the 5.3L and the 6 Speed. The other day I was wheeling in 4-Low and the transmission went up to 225. I pulled over and it took forever to cool back to about 210. I'm not happy about this, and I too plan to install an aftermarket cooler, and perhaps also delete the thermostat. Are you doing a thermostat delete?

I don’t think 250 is anything to worry about on the transmission. Modern fluids are designed to handle that no problem, and if your transmission was overheating it would probably tell you… just my 2 cents

I was not aware the Trail Boss were available with a 6 speed auto? I was sure all the TB's were 10 speeds? Are you certain it is a 6l80? Also, what engine do you have?

I meant to ask you last time about the dealership that did the 2 inch lift up front. Will that void the suspension warranty. I assume they would try to weasel out of by blaming that but just curious if it came up. Hope it works for you can’t believe shit is overheating in 75 it was 105 here today lol. Would kill for 75

I have a 2021 with the 2.7 turbo... yes go ahead and laugh and make fun of me I'll take it 😁 my transmission fluid runs at 215 and it slowly gets to that after 20 mins of driving. I didn't think that was normal I called my dealership and they said it's totally normal. What ya'll think?

Damn man. I'm pretty hard on mine with over 7k of abuse with no issues yet. It's the 5.3 though.

I jus bought a 2022 Chevy 1500 custom 2wd and wondering is it normal for my trans to stay at 195 jus got 2 days ago just curios bc it stays their never moves

Hey brother I’m having the same issue on my 2021 Silverado Rst 5.3 engine 10 speed automatic.. my transmission climbs all the way up too 250-265.. haven’t regeared it yet do you think installing a after market cooler might help? Was thinking of getting a transmission oil change as well also I am running 35x12.5x18 in tires rims

Does yours need the updated thermostat that opens at 120 instead of 190

4Lo for extended periods might be a clue to over heating

That’s bearly a dirt road, why were you in 4wd?

I'm about 100 percent sure that u do not drive in 4 low like that at all , u really should have kept it in 4 high, 4 low is really for rock or sand . The only time I use 4L is at the river in the sand and when I'm going up a steep hill looking at the sky .

Off course you put it on 4 low !!

What should be the normal temperature?

Is it the altitude? 🤔 Im really curious now!

Is this jackson hole?

Mine the same thing, these transmissions are junk.

Did you say you were running it in 4 low?

This is why I hate hate hate hate hate automatic trucks. The transmissions always overheat. Even the diesels do. Sucks