What was found
AT 3000 AGL DURING THE AFTER-TAKEOFF CHECKLIST, THE GEAR LEVER WAS MOVED TO THE OFF POSITION, DURING WHICH THE RT MLG EXTENDED, & GEAR DISAGREE LIGHT ILLUMINATED GEAR EXTENDED NORMALLY WILL PLACE GEAR ON MEL 32-30-1.MTX DEFERRED LANDING GEAR RETRACTION SYSTEM IAW MEL 32-30-1 MX PROCEDURES C/W PLACARDS INSTALLED MLG TO REMAIN EXTENDED. A/C REMAINS NO ETOPS. ACFT FLOWN TO CVG FOR MAINT & DIVERTED TO PIT BECAUSE OF FUEL BURN, THEN CONTINUED TO CVG. REMOVED AND REPLACED RT MLG DOOR IAW AMM 32-12-01. COMPLETED RT MLG DOOR INSTALLATION & RIG IAW AMM 32-12-00 OPS CHKD GOOD. PREFORMED NLG AND MLG RETRACTION TEST & EXTENSION IAW AMM 32-32-00 OPS CHKD GOOD. ACFT RETURNED TO SERVICE.