It could be your rear breaks / including the emergency breaks, or your rear differential
brake shoes or pads are worn and need replacing
that could be a variety of things, wheel bearings, u joints, rear end...
The Grinding noise in the passenger rear of a 2002 Explorer is most likely either a bad wheel bearing, or a brake problem. Check the brakes then the bearing to find the cause.
Brake linings worn out or wheel bearing is bad
The 2006 Lincoln Navigator has 39.7 in. of rear head room.
The 2001 Lincoln Navigator has 62.3 in. of rear hip room.
The 2008 Lincoln Navigator has 39.7 in. of rear head room.
The 2001 Lincoln Navigator has 39.8 in. of rear head room.
The 2002 Lincoln Navigator has 64.4 in. of rear shoulder room.
The 2005 Lincoln Navigator has 39.7 in. of rear head room.
The 2011 Lincoln Navigator has 63.7 in. of rear shoulder room.
The 2012 Lincoln Navigator has 39.1 in. of rear leg room.