Chrysler is recalling certain model year 2009-2012 Ram 1500 trucks manufactured from February 27, 2008, through June 30, 2009, and from December 1, 2009, through October 20, 2011; model year 2009-2011 Dodge Dakota trucks manufactured from February 27, 2007, through June 30, 2009, and from December 1, 2009, through September 30, 2011; model year 2009 Chrysler Aspen trucks manufactured from January 3, 2008, through December 18, 2008; and model year 2009 Dodge Durango trucks manufactured from January 3, 2008, through December 18, 2008. The rear axle pinion nut may loosen due to an undersized pinion spline that can allow relative motion between the nut and companion flange.