Jimmie Johnson won Sunday's AAA Texas 500 while championship contenders Jeff Gordon and Brad Keselowski, as well as their teams, were involved in a post-race fight on pit road.  The two clashed in the closing laps at Texas Motor Speedway.  Johnson scored his record fourth Sprint Cup Series win at Texas, including his third straight in the fall race.  Kevin Harvick grabbed second from Keselowski on the final lap but crossed the finish line a half second behind Johnson.  Keselowski finished third, followed by Kyle Busch and Jamie McMurray.  Gordon approached Keselowski on pit road following the race then a brawl between both drivers and their pit crews ensued.  Sunday's race at Texas was the second event in the Eliminator Round of the Chase for the Sprint Cup championship.  The third is at Phoenix International Raceway on Sunday.