PACCAR IS RECALLING CERTAIN MODEL YEAR 2011-2012 KENWORTH T270/370, T440/T470, T800, T660, W900 AND C500 VEHICLES MANUFACTURED BETWEEN OCTOBER 18, 2010, AND JANUARY 28, 2011. CERTAIN CAST IRON SLACK ADJUSTER HOUSINGS, WHICH TRANSMIT BRAKING FORCE FROM THE BRAKE CHAMBER PUSH ROD TO THE BRAKE CAM TUBE, MAY INCLUDE A FLOW NOTCH IN THE HANDLE PORTION OF THE HOUSING DUE TO AN ERROR DURING THE CASTING PROCESS. A FLOW NOTCH IN THE HANDLE PORTION MAY REDUCE THE EFFECTIVE CROSS SECTION STRUCTURE AND CAUSE THE SLACK ADJUSTER HOUSING TO FRACTURE.