Is this normal while in 4x4?

alright thanks dorifuto.

The truck is 5 years old and only 27k miles...

 

Its all about differentials. As noted AWD's have front to back differentials to allow for the front and rear wheels to spin at different speeds just like the side to side differential(s) on most every vehicle do. PT 4WD's only have side to side differentials. This only matters when turning.

Speed is not the issue. Turning is. I live in Oregon where studded tires and rain make for some fun highway driving. My 98 Tacoma has spent many miles at 70-75 in 4WD on wet roads with minimal turns. I pay for it, I like to use it. When I get off the highway I go back to 2WD unless its really bad. And I spent three years crossing a local pass and had it in 4WD a lot when the temps drop and conditions are hard to discern. Its made 230k with no problems and I missed more than a few monthly runs on the 4WD.

Dry pavement is not great for 4WD but if you have to run on it for a few miles each month with not sharp turns to work the front it won't hurt anything on a Toyota. Can't speak for other brands............