I just brought my Jeep in to the shop with a similar problem. When the Jeep was in 4-wheel drive, all 4 wheels would stop turning when I stepped on the brakes, but when I had it in 2-wheel drive and locked it up (on ice) only the front wheels would stop turning. My mechanic said that the rear brake adjusters were bad. The fix required two rear brake adjuster kits (about $30 each) and some other hardware like springs and whatever else. Parts and labor ran $340.
becasuse its a rear wheel drive vehicle
The 2010 Jeep Wrangler has four wheel drive.
The 2005 Jeep Wrangler has four wheel drive.
The 2011 Jeep Wrangler has four wheel drive.
The 2012 Jeep Wrangler has four wheel drive.
The 2014 Jeep Wrangler has four wheel drive.
The 2013 Jeep Wrangler has four wheel drive.
The 2006 Jeep Wrangler has four wheel drive.
The 2007 Jeep Wrangler has four wheel drive.
The 2002 Jeep Wrangler has four wheel drive.
The 2009 Jeep Wrangler has four wheel drive.
The 2004 Jeep Wrangler has four wheel drive.