VEHICLE DESCRIPTION: HEAVY DUTY TRUCKS BUILT WITH REAR LEAF SPRING SUSPENSIONS (MODELS 4700 BUILT WITH REAR LEAF SUSPENSIONS AND MANUFACTURED FROM DECEMBER 9, THROUGH DECEMBER 16, 1998; MODELS 3400 AND 3800 BUILT WITH 14SBK REAR LEAF SPRING SUSPENSIONS AND BUILT APRIL 14 THROUGH MAY 10, 1999; AND MODELS 3400 AND 3800 BUILT WITH REAR LEAF SPRING SUSPENSIONS AND MANUFACTURED FROM MAY 10 THROUGH MAY 18, 1999). ON VEHICLES WHERE THE FRAME TO AXLE HOSE LENGTH WAS TOO LONG, A CHAFING CONDITION EXISTS ON SUSPENSION COMPONENTS, WHICH COULD RESULT IN HOSE RUPTURE. ON VEHICLES WHERE THE HOSES ARE TOO SHORT, A HOSE SEPARATION COULD OCCUR WITH SEVERE SUSPENSION ARTICULATION.