AWD Disengaged

There is also a grinding noise when we make slow Mostly right turns with the foot on the brake.

A fault code will be stored in the abs module, scanning it for the code(s) is the starting point for diagnoses, with your vehicle, when a abs fault code is stored, the system shuts down along with all wheel drive. A very common problem with that vehicle is a wheel speed sensor failing. But would need scan to be sure. As for noise, sounds like possible worn out brakes, or could be possible bearing.

Don't know if you found this out yet, but it is definitely one of the front hubs. The hub/bearing assembly also has the ABS sensor attached, so if any of the three components fail, it needs to be replaced. I have to replace mine about every 40K miles (due for one now, in fact).

It's recommended to do them both at the same time, but I haven't.

This fix works about 95% of the time! I have the resolution to your AWD disable light and grinding noise problem. You have a bad oil flow valve/sensor, which connects to the bottom of the rear differential. The rear differential fluid has to be drained and refilled with 4 bottles of 16oz versatrak dealer only fluid. Next, drive the vehicle in 4 tight figure 8's, then driven 10 miles. Come back and drain the fluid again and this time install the new oil flow valve/sensor. Next, refill the rear differential fluid with 4 bottles of 16oz versatrak. The AWD disable light should go off and you need to drive in 4 tight figure 8's and the grinding will stop immediately or after driven 1,000 miles. The flow valve and 8 bottles of fluid will set you back about $650, labor not included. GM/ASE 33 years experience, not an Internet only mechanic!