I have a 2000 blazer lt I’m getting a metal rubbing/scrapping sound from the front and it gets louder the higher the rpms. It only makes the noise in 2wd and up to 55km/ about 40mph as soon as I put it in 4hi the sound goes away if I’m moving and put it in neutral it stops also it started about 2 weeks ago. Any idea what it could be it has about 152k miles on it