What was found
GEAR RETRACTED NORMALLY ON DEPARTURE LT MAIN THEN EXTENDED ON CLIMBOUT. RAN LANDING GEAR DISAGREE CHECKLIST ALL GEAR REMAINED RETRACTED WITH GEAR HANDLE IN UP POSITION. ACFT GROUNDED. REMOVED AND INSTALLED A NEW ACTUATOR PIN AND BEARINGS TO LT MLG UPLOCK LINK ASSY. REQUIRES GEAR SWING REF AMM 32-32-31-404-056 9C (1) (I-K) AND COTTER PINS INSTALLED. NEW LT MLG UPLOCK SENSOR WAS INSTALLED, ACCOMPLISHED TEST OF THE LANDING GEAR POSITION INDICATING AND WARNING SYS AND OPS TEST OF LT MLG IAW AMM 32-61-00-725-001 & OPS CK GOOD.