ODI CONDUCTED THIS INVESTIGATION TO INVESTIGATE WHEEL SEPARATIONS OCCURRING IN CARGO TRAILERS. IN 2003, ODI IDENTIFIED A PROBLEM WITH WHEEL SEPARATIONS OCCURRING IN RECREATIONAL VEHICLES (EA04-009, EA04-019, EA04-032) AND, IN AUGUST 2004, EXTENDED THE INVESTIGATION ACTIVTY TO CARGO TRAILERS EQUIPPED WITH SIMILAR WHEEL END COMPONENTS AS THE RECREATIONAL VEHICLES THAT HAD EXPERIENCED WHEEL SEPARATIONS.PACE AMERICAN HAS PROVIDED INFORMATION TO ODI (4 INCIDENTS INMODEL YEAR 2003 VEHICLES AND 1 INCIDENT IN MODEL YEAR 2004 VEHICLES) THAT INDICATES A SMALL BUT PERSISTENT NUMBER OF SEPARATION INCIDENTS HAVE OCCURRED IN PACE AMERICAN VEHICLES.THE OVERALL INCIDENT COUNT IS SMALL.HOWEVER, VEHICLES EQUIPPED WITH ALUMINUM WHEELS CONSTITUTE A SIGNIFICANTLY HIGHER SEPARATION RATE THAN VEHICLES EQUIPPED WITH STEEL WHEELS.ODI IS UPGRADING PE04-058 TO AN ENGINEERING ANALYSIS TO REQUEST FURTHER INFORMATION FROM PACE AMERICAN.ODI WILL ALSO CLOSELY MONITOR THE WHEEL SEPARATION PERFORMANCE AT PACE AMERICAN FOR THE NEXT 12 MONTHS.