If it has an engine oil cooler, I'd "know" that 0W20 would be fine. If it didn't, I'd "feel better" with something thicker. And regardless I'd just use xW30.
It's a single run in a vehicle that has some indication of being used as a work vehicle. Toyota does not just toss out 0W20 for fun (I'm not sure any of the OEM's did). Day in and out towing, sure I think xW30 is better. One run though and I don't see the problem. Since you can plan ahead, I'd run the thicker, but I wouldn't lose sleep if you suddenly towed with "thin" oil.
Originally Posted by Bryanccfshr
Everything in the driveline is taking additional stress.
The truck will have to be run in a lower gear to maintain interstate speeds, especially with headwinds and hills, by keeping it in a higher bar you risk excessive shifting with an auto, and lugging the engine under load.
So properly running the transmission in a lower gear means the engine will be turning at sustained higher than normal rpms. Which means it is creating more heat. It is a good idea to run a thicker oil in this situation. Because fuel mileage is no longer a concern..
Towing a similar trailer a couple of weeks ago expect gas mileage to drop. In half. I averaged 10-11 mpg with a fully loaded 6x12 loaded enclosed trailer with a mild headwind. Maintaining 65-70 for 250 miles.
That's a good point, if this thing is winding out for 3,500 miles then, if nothing else, a short OCI is in order, like 5k.
OP, is this an auto or stick?