What was found
STALL CHECK: DURING PREFLIGHT SPS SYSTEM CHECK, WITH LEFT AND RIGHT TEST SWITCHES IN TEST, STICK SHAKER ACTIVATED BUT WE HEARD, AND CO-PILOT FELT, A TAPPING/BANGING UNDER HIS RIGHT FOOT. ADDITIONALLY, THE PUSHER FAILED TO ACTIVATE. WE TESTED A SECOND TIME AND SHAKER ACTIVATED, TAPPING HEARD BUT PUSHER, AFTER A 1 TO 2 SECOND DELAY, ACTIVATED. WE DEPRESSED THE AP/SP DISC BUTTON, PUSHER, AFTER A 2 TO 3 SECOND DELAY, RETURNED APPROX. HALF WAY AND STOPPED MIDWAY OF THE RETURN TRAVEL, DELAYED IN THAT POSITION APPROX. 2 SECONDS AND THEN FULLY RETURNED. CO-PILOT STATED HE FELT A GRINDING THROUGH THE CONTROL COLUMN AS IT RETURNED TO THE NORMAL POSITION. G SWITCH TEST ALSO FAILED AS THE PUSHER WOULD NOT RELEASE. (STALL VANES WERE CHECKED FOR NORMAL STREAMLINED POSITION, AND THEY WERE NORMAL)