What was found
ON TAKE OFF, LANDING GEAR WAS SLOW TO RETRACT MADE LOUD SQUEALING NOISE, SEQUENCING ON THE RETRACT WAS OFF, & THE ROLL SPOILER OUTBOARD CAUTION & #2 HYD ISO VALV CAUTION BOTH ILLUMINATED. AFTER THE GEAR WENT UP, BOTH LIGHTS EXTINGUISHED & EVERYTHING APPEARED NORMAL. ON ARRIVAL, GEAR WAS SELECTED DOWN, & THE EXACT SAME THING HAPPENED AGAIN. 3 GREEN WAS INDICATED ON THE MAIN GEAR SELECTOR, & A NORMAL LANDING WAS ACCOMPLISHED. REMOVED FROM SERVICE. REPLACED #2 HYD SYSTEM ISOLATION VALVE AND #2 HYD SYSTEM RESERVOIR. OPS CHECK GOOD. RETURNED TO SERVICE.