Scotty, I drive a 2021 Chevy Silverado RST. And yes I know how you feel about General Motors hahaha. I recently wanted to test out 4wd high at a stoplight and see how quickly I could get the thing moving. I got up to pretty high speeds (75-80mph) before I started slowing down. A buddy of mine told me you should never go over 55-60mph in 4wd high. I’ve also read online that there is no limit. I’m wondering what your thoughts are on this. Did I ruin my transfer case or anything?
Yeah you generally want to avoid using 4WD at high speed, and on dry pavement. If you think about it, 4WD was designed for low traction situations/challenging terrain/getting unstuck. In other words, situations where you're going slow. If you want to drive around all the time like that, then that's what AWD is for.
But the specifics about that stuff depends on your particular unit. You really ought to consult your owner's manual for these things. Not random people on the internet. The manual exists to tell you how to operate your vehicle.
You probably didn't ruin anything yet, but if you abuse them too much they do eventually blow up, and they're not cheap. I've seen transfer case pumps that have chewed a hole right through the housing. I've also seen those heavy chains inside fly apart and the carnage they create is spectacular.
You would know if you destroyed the transfer case. They're usually chain driven with gears. Gear teeth break, the chain snaps, etc. That's all extremely loud and violent at high speed. As @Mmj says, the bigger danger on dry roads is making turns with the 4×4 engaged. That binds up the drivetrain, and it will destroy all kinds of expensive stuff in time. It's not All-Wheel Drive. Use it in RWD only unless you're stuck, etc.
