What was found
ON TAKE OFF, TRAILING EDGE FLAP DISAGREE EICAS MSG WHILE MOVING FLAPS FROM 5 TO 1. FOLLOWED QRH PROCEDURE. FLAP WORKED FINE ELECTRICALLY. AIR TURNBACK. LANDED WITHOUT FURTHER INCIDENCE. AIRCRAFT GROUNDED BY MAINTENANCE. MAINTENANCE FOUND THE FLAP/SLAT SHUTOFF VALVE STICKING DURING OPERATION. REMOVED AND REPLACED FLAP/SLAT SHUT OF FVALVE IAW B767 AMM 27-57-48. OPS CHECK GOOD. VERIFIED FLAP/SLAT MOVEMENT MULTIPLE TIMES. MOVED FLAP HANDLE ONE DETENT AT A TIME AND FROM 0 TO 30. NO ISSUE PRESENT. RAN FLAPS ELECTRICALLY WITH NO ISSUES. NO LEAKS NOTED. A/C RELEASED CAT I PENDING MCDP 30/40 TEST. THE AIRCRAFT WAS RETURNED TO SERVICE FOLLOWING A SUCCESSFUL TEST FLIGHT.