TEREX IS RECALLING 1,167 TC SERIES AERIAL DEVICES EQUIPPED WITH CHECK VALVE, P/N 443847, INSTALLED FROM SEPTEMBER 2001 UNTIL MARCH 2007. THE VALVE IS LOCATED ON THE LOWER BOOM LIFT CYLINDER. FAILURE CAN OCCUR ONLY WHEN THE VEHICLE IS PARKED AND THE AERIAL DEVICE IS IN OPERATION. THE CHECK VALVE IS USED IN RETIMING OF THE BOOM WHEN THE PLATFORM IS OUT OF LEVEL. THE FLOW THROUGH THE CHECK VALVE CAN CAUSE THE SNAP RING TO FAIL IF THE RETIMING FLOW IS ABNORMALLY HIGH. THE CHECK VALVE COMPONENTS WILL FLOW INTO THE LIFT CYLINDER IF THE SNAP RING FAILS.