I get that mentality. The 2017 Rebel I used to own didn't have the full-time 4wd transfer case, so auto 4wd wasn't an option. I only selected 4wd when it was needed. Auto 4wd is more like awd, and is designed to be usable full time. I've had it on two trucks since owning that Rebel, and neither one made noises when using auto 4wd. It's not normal for it to make noises LOL.
Depends on how you drive i guess lmao.