BMW X5 2013. only have done oil changes every year. When accelerating - consistently around 1500 to 1600 RPMs there is a grinding or gurgling noise as it tries to shift gears. So it’s under load. When I got an oil change, the mechanic said not to worry about it.
And apparently you are worrying about it, right? You are correct to worry. Something cheap can become very expensive if ignored.
Take the SUV to a real mechanic, not an oil changer, and have them check it over. It could be a lot of things, none of which we could identify over the internet. Expect to pay for their time spent trying to diagnose the noise but it is money well spent.