ON INITIAL CLB AFTER TKOF FLAPS RETRACTED ON SCHEDULE UNTIL 2 DEGS TO UP WAS SELECTED. WITH UP SELECTED VIBRATION WAS FELT; XCTL INPUTS WERE USED; AMBER LEADING EDGE DEVICE LIGHT STAYED ILLUMINATED; AND SO AUX PANEL LEADING EDGE INDICATED GREEN LIGHT ON #2 LEADING EDGE SLAT CONFIRMING ITS EXTENSION. DECISION WAS MADE TO RETURN AND LAND. ALL CHKLIST WERE COMPLETED; FUEL WAS DUMPED TO BELOW MAX LNDG WT. THE LNDG WAS UNEVENTFUL EXCEPT EMER CRASH CREW WAS ACTIVATED BY THE TWR.

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ON INITIAL CLB AFTER TKOF FLAPS RETRACTED ON SCHEDULE UNTIL 2 DEGS TO UP WAS SELECTED. WITH UP SELECTED VIBRATION WAS FELT; XCTL INPUTS WERE USED; AMBER LEADING EDGE DEVICE LIGHT STAYED ILLUMINATED AND SO'S AUX PANEL LEADING EDGE INDICATED GREEN LIGHT ON #2 LEADING EDGE DEVICE L SIDE CONFIRMING ITS EXTENSION. SLOW CLB WAS CONTINUED TO 8000 FT WITH REF MANUAL REFED AND ATC NOTIFIED OF OUR PROB AND POSSIBLE FUEL DUMP AND RETURN. WE WERE CLRED TO 6000 FT -- COMMUNICATED WITH LEAD FLT ATTENDANT; FLT ATTENDANTS; PAX; DISPATCH; AND ATC AS FUEL DUMP COMMENCED. AFTER TERMINATION COM CONTINUED WITH FLT ATTENDANTS; PAX; AND ATC AND RETURNED FOR A NORMAL VISUAL APCH AT MAX CERTIFIED LNDG WT. CRASH EQUIP WAS STANDING BY (ALTHOUGH THEY WERE NOT REQUESTED). THIS MADE IT NECESSARY TO COMMUNICATE THIS TO FLT ATTENDANTS AND PAX; AS THIS WAS A SURPRISE TO US AFTER NOT REQUESTING IT AND WE DID NOT WANT IT TO BE A SURPRISE TO THEM. ALTHOUGH THIS PROB COULD NOT BE DUPLICATED ON THE GND -- THE DISCREPANCY WAS A REPEAT ITEM (SEVERAL TIMES) AND MAINT AGREED TO TAKE THE PLANE OTS.