VEHICLE DESCRIPTION: AIRCRAFT RESCUE FIRE FIGHTING TRUCKS EQUIPPED WITH ARVINMERITOR AXLES BUILT WITH TRW TIE ROD BALL-SOCKET BEARINGS, PART NO. TRW 24 DL. THESE BEARINGS HAVE A BELOW SPECIFICATION CASE DEPTH AND/OR HARDNESS WHICH CAN LEAD TO PREMATURE WEAR OUT OF THE SOCKET IN SOME APPLICATIONS.