The Office Of Defects Investigation (ODI) opened RQ06-005 based on four consumer reports of alleged ball joint failure. The complaints allege that a front suspension ball joint separated while driving, which caused the suspension to collapse and resulted in a loss of vehicle control. All of these complaints involved the failure of a lower tension-type ball joint. During the investigation there were 39 (36.7 per 100,000 vehicles) complaints and 74 (69.6 per 100,000 vehicles) warranty claims for the 2004 model year (my) Toyota Tundra. Further analysis showed that the average failure mileage was 54,025 miles, and that of the 109 unique ball joint separation incidents, 64 (133 per 100,000 vehicles) were on four-wheel drive vehicles, which make up approximately 45% of the 2004 my population (106,346 vehicles). The remaining 55% are two-wheel drive vehicles which experienced a total of 45 (77 per 100,000 vehicles) ball joint separations. Also, throughout the investigation there surfaced additional failures which have prompted ODI to upgrade this investigation to an engineering analysis and widen the scope of the affected population to include 2004-2005 my.this recall query has been upgraded to an engineering analysis (EA06-014) to further investigate this issue to assess the safety-related consequences, and to determine the scope of the affected population.