What was found
AT 2800 FT , JUST AFTER GLIDESLOPE CAPTURE FOR ILS WITH CTR AUTOPILOT ENGAGED, AUTOPILOT ABRUPTLY PITCHED DOWN TOWARD F/D, COMMAND INDICATING 8 DEG. NOSE DOWN. AUTOPILOT NAV DISCONNECTED MANUALLY TO MAINTAIN AIRCRAFT CONTROL. GLIDESLOPE INDICATION SHOWED ON GLIDESLOPE THROUGH OUT. PERFORMED MCDP TEST 30 AND 40 IAW MM 22-00-02, NO FAULT NOTED. OK FOR SERVICE.