A B737-300 IN CLB AT 1200 FT EXPERIENCED A NOTICEABLE R WING DOWN CONDITION THEN A L WING DOWN CONDITION FOR A PERIOD OF 10 SECONDS.

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ON TKOF CLBING THROUGH 1200 FT A NOTICEABLE R WING DOWN AILERON INPUT WAS REQUIRED FOR 10 SECONDS TO KEEP WINGS LEVEL FOLLOWED BY A REVERSE TO A L WING DOWN AILERON INPUT FOR 10 SECONDS. DURING THIS PERIOD NO RUDDER PEDAL DISPLACEMENT WAS NOTED NOR WERE THERE ANY UNUSUAL DISCREPANCIES IN THE FLAP/SLAT RETRACTION SEQUENCE OR ENG PARAMETERS. THIS SAME SIT OCCURRED ON OUR PREVIOUS LEG FROM ATL TO TLH; JUST FOLLOWING A BRIEF AND MILD ENCOUNTER WITH WAKE TURB. AT THAT TIME I CONSIDERED THE WAKE TURB TO BE THE CAUSE OF THAT INPUT. HOWEVER; AFTER THE SAME THING OCCURRED AGAIN LEAVING TLH IN SMOOTH AIR; I DECIDED IT WAS TIME TO WRITE THIS UP. NEITHER EVENT WAS EXCESSIVE OR ABRUPT BUT I FELT NEEDED THE ATTN OF OUR MAINT. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE 10 SECOND R AND L WING DOWN MANEUVER HAPPENED TWICE. THE RPTR SAID IT FIRST HAPPENED IN TURBULENT AIR AND THE SECOND TIME IN STILL AIR. THE RPTR SAID MAINT REPLACED THE RUDDER PWR UNIT; CHKED FLAP AND SLAT RIG AND OP. THE RPTR STATED THE FLT TEST WAS NORMAL.