What was found
AIRCRAFT WAS GROUNDED: AN EMERGENCY WAS DECLARED DUE TO: ON CLIMB OUT, PASSING 5000FT AND MAINTAINING 250KTS ENGAGED AUTOPILOT-B. A BUMP WAS FELT, AND THE AIRCRAFT WAS THEN UNABLE TO MAINTAIN PITCH AND AIRSPEED. AUTOPILOT WAS DISCONNECTED AND THE AIRCRAFT WAS HAND FLOWN. THEN AUTOPILOT-B WAS REENGAGED WITH THE SAME RESULT. STAB OUT OF TRIM LIGHT ILLUMINATED. AIRCRAFT AIR INTERRUPTED BACK TO AND LANDED SAFELY AT ORD. **SUPPLEMENTAL REPORT FOR (AALA202506178071): REMOVE AND REPLACE THE AUTOPILOT-B ACTUATOR UPPER ASSEMBLY (AALA202506178071), PER AMM 22-11-26. ADDITIONALLY, REPLACED THE HYDRAULIC PRESSURE SWITCH ON THE AUTOPILOT ACTUATOR-B (AALA202506259622), PER AMM 22-11-40. OPERATIONAL AND LEAK CHECK GIS OOD AT THIS TIME. NO ACTIVE FAULTS NOTED ON DFSC SYSTEM AT THIS TIME**(CLOSED).