What was found
PASSING 32,000 ON CLIMB OUT, WITH LT AUTOPILOT ENGAGED, RECEIVED A/P EICAS ALONG WITH A/P LIGHT ON UPPER FORWARD INST PANEL. A/P REMAINED ENGAGED. DISENGAGED A/P & REENGAGED LT A/P. AFTER PASSING 36,000 RECEIVED A/P EICAS AGAIN. MANUALLY DISCONNECTING A/P 2ND TIME NOTICED ACFT WAS OUT OF TRIM. REQUIRED UP ELEV TRIM TO RE-TRIM. LT A/P WORKED FINE DURING CRUISE BUT ONCE DESCENT WAS STARTED, RECEIVED A/P EICAS REPEATEDLY. DID RECEIVE LAND 3 ON APPR & GOOD CAT 1 AUTOLAND RAY 27 MEMPHIS RVR 6000. WIRING CHECKS GOOD, & PERFORMING DAR TESTING AS NOTED ON MTSI 22-23/0557. NO SHORTS TO GROUND NOTED & DAR TEST PASSED. R & R S27L HYD SYS LOW PRESS SWITCH IAW AMM 29-11-17-4. OPS & LEAK CHKD GOOD.