My Silverado is having issues with the 4x4. It does Engage but it struggles. When I set the 4h it kinds of drags like something is holding it back and it makes a weird sound coming from the front end. If I set it to 4l it really doesn’t want to move. I have to give it a nice amount of gas for it to go but is feels like something is holding the truck from moving. I’m looking for ideas to pin point the issue. Thank you