Toyota Motor Corp. is recalling more than 378,000 full-size Tundra pickup trucks manufactured between 2004 and 2006 that may develop serious steering problems. It is part of a larger recall of 533,000 pickups and sport utility vehicles that caused six injuries. The Japan-based manufacturer says that the front-suspension defect stems from improperly finished ball joints, which may wear out prematurely and cause hard steering, noise, misalignment and joint separation. The fix is free to owners and takes about three hours. Toyota recalled about 768,000 pickups and SUVs in 2005 for similar reasons.