Probably depends on if your Gladiator is a mall crawler or use it for exploring. Don't wanna be in the thick of it and stuck with a 31 in street tire trying to get through mud and ruts. I plan to upgrade mine.
I have the same noise in mine. Seems to happen more often with higher revs or quicker shifts. I've even had it happen coming out of first and second too. No idea what it is. Doesn't happen all the time. Nothing seems to be not working, just making a noise.
My son works at a Jeep dealer, I asked him the same question. He said they charge $25 an hour for 8 hours. Not sure why it would take that long. Check different dealers. The 4 hours sounds more believable.