Growl noise in 4 wheel drive

I’m new here. Yea I’m a girl but I also like to try to work on my own Jeep when I can. It has high miles 230…. Some thousand miles, old but runs good. I mainly use it now for trailing and pulling pop up camper once in a while, trips around town. Definitely not my every day driver. No big mudd holes or anything like that but I’ve never been afraid to put it in 4 wheel drive and run it up a hill on a power line, nothing bad or straight up just a good size hill that may or may not have sand or holes. It does great in sand as well. I don’t run it hard or constant in 4 wheel when I’m out on the trails. I run 265 70 17 ATs. Well a while back it started to growl in 4 wheel drive it also does it in part time. I’ve had someone say they don’t know, even that it was normal, “it’s not normal” or that the chain could be stretched? Any idea please.