A few days ago my t-case started to make this loud grinding noise in reverse and drive. I've had the truck for about 8 months and it has 329k miles. It only makes that sound when the engine is warm and stops as soon as I start moving . 4 high and low still work. I changed the T-case fluid and it got slightly quieter, but I'm at a loss as to what is causing it. Any ideas? Or is it just that my T-case on the way out?

 

If the transmission is in park, it's not your transfer case making noise.