What was found
AFTER TAKEOFF WHEN GEAR RETRACTED, ALL 3 GREEN EXTINGUISHED, INTRANSIT LIGHT CAME ON AND HYDRAULIC PUMP TURNED ON. GEAR DID NOT LOCK UP QRH COMPLETED, GEAR RECYCLED, RETRACTED AS NORMAL. AIR RETURN TO DEPARTURE. FOUND SIGNIFICANT ICE ACCUMULATION ON RT LANDING GEAR. EVIDENCE THAT A LARGE CHUNK OF ICE RECENTLY BROKE AWAY AT RT UPSTOP PAD ON SHOCK STRUT, EXPLAINING WHY A SECOND RETRACT ATTEMPT WAS SUCCESSFUL. GEAR RETRACT CHECKS GOOD.