As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PASSING 17,000 IN CLIMB ON AUTO PILOT B IN VNAV AND LNAV, AIRCRAFT BEGAN ROLLING LEFT REQUIRING MANUAL INTERVENTION. DISCONNECTED AUTOPILOT B, RE-ESTABLISHED LATERAL CONTROL. ENGAGED AUTOPILOT BUT ONLY HAD "CWS" MODE EVENTUALLY LOST BOTH AUTOPILOT B & A AND BOTH FLIGHT DIRECTORS COMPLETED FLIGHT HAND FLYING RAW DATA. ADJUSTED AUTOPILOT AILERON ACTUATOR A ROD ASSEMBLY IAW AMM.