What was found
EMERGENCY DECLARED & LANDING UNEVENTFUL. ACFT NOT OVERWEIGHT. DURING CLIMB RECEIVED A SLAT OVERSPEED WARNING & DISAGREE LIGHT ILLUMINATED WHILE ACCELERATING THROUGH 280 KNOTS. AUTOPILOT WOULD NOT HOLD ATTITUDE. FLIGHT CONTROLS WERE VERY HEAVY WHEN AUTOPILOT DISENGAGED. ACCOMPLISHED QRH. WHEN FLAPS MOVED TO 11 DEGREES DISAGREE LIGHT WENT OUT & TAKEOFF ILLUMINATED. PERFORMED BITE CHECK OF PROXIMITY SWITCH ELECTRONIC UNIT, CHECK OF SENSORS C & D IAW AMM 27-80-06 & CHECK OF FLAP SLAT INDICATOR IAW AMM 27-80-00-201 WITH NO FAULTS FOUND.