A B737-700 ON APCH AT 11000 FT WHILE ATTEMPTING TO COMMAND FLAPS 1 GOT FLAP SHUTOFF ASYMMETRY CONDITION. CAUSED BY LEFT FLAP POSITION TRANSMITTER.

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UPON REACHING 210 KTS; I COMMANDED FLAPS 1. WHILE SELECTING FLAPS 1; ATC GAVE US TFC AND SEQUENCE INFO. ANTICIPATING A SHORT APCH; I COMMANDED FLAPS 2. THE ACFT HAD A SLIGHT ADVERSE YAW MOMENT; SIMULTANEOUSLY I LOOKED AT THE FLAP INDICATOR ON THE CENTER PANEL AND OBSERVED A FLAP ASYMMETRY CONDITION. THE LEFT FLAP WAS ABOUT 90% TO FLAPS 1 AND THE RIGHT ONE DIDN'T APPEAR TO MOVE MUCH AT ALL. THE LE FLAPS TRANSIT LIGHT APPEARED TO FLASH ONCE 'INTERMITTENTLY;' BUT WITHOUT A LE FLAPS EXT LIGHT. THE OVERHEAD FLAP PANEL SHOWED AN ALL GREEN CONDITION. I ASKED THE CAPT TO REFERENCE THE QRH AND ACCOMPLISH THE FLAP ASYMMETRY CHKLIST. I INFORMED ATC OF OUR SPLIT FLAPS CONDITION AND REQUESTED THE LONGEST RWY; DELAYING VECTORS TO ALLOW TIME TO ACCOMPLISH CHKLISTS AND COORDINATE WITH DISPATCH AND MAINT CTL. WHILE GETTING VECTORS; I DECIDED TO INCREASE BANK ANGLE TO 30 DEGS IN ORDER TO IMPART A BIT MORE 'G' ON THE ACFT; IN HOPES THAT THIS WOULD ALLEVIATE OUR FLAP ASYMMETRY CONDITION. IT WORKED; WITH BOTH FLAPS INDICATING 'APPROXIMATELY ONE.' WE CROSS CHECKED OVERHEAD FLAP LED INDICATORS AND OBSERVED AN ALL GREEN CONDITION. I COMMANDED FLAPS 2 AND FOUND NO MOVEMENT AT ALL. WE MOVED THE HANDLE BACK TO FLAPS 1 POSITION AND CONTINUED TO COORDINATE WITH MAINT DISPATCH . WE REFERRED TO THE ALTERNATE FLAPS CHKLIST AND PLANNED A FLAPS 15 LNDG. THIS CHKLIST WAS ACCOMPLISHED AND AN UNEVENTFUL FLAPS 15 LNDG WAS ACCOMPLISHED. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE CAUSE OF THE ASYMMETRICAL FLAP SHUTOFF WAS CAUSED BY THE LEFT TRAILING EDGE FLAP POSITION TRANSMITTER. THE RPTR SAID WHEN THE TRANSMITTER WAS ASSEMBLED BY THE MANUFACTURER; GREASE WAS ADDED THAT WAS NOT TESTED FOR WATER ABSORPTION AND AS A RESULT; THE WATER FREEZES AND LOCKS THE TRANSMITTER. THE RPTR STATED THIS GREASE PROB IS LIMITED TO THE B737-700 EXCLUSIVELY. CALLBACK CONVERSATION WITH RPTR ACN 634632 REVEALED THE FOLLOWING INFO: THE RPTR STATED THE LEFT FLAP TRANSMITTER WAS THE CAUSE OF THE ASYMMETRICAL FLAP SHUTOFF. THE RPTR SAID A SERVICE BULLETIN DESCRIBES THE PROB AS INTERNAL TRANSMITTER GREASE FREEZING UP DUE TO INTERNAL WATER ABSORPTION. THE RPTR STATED THIS GREASE PROB IS ONLY FOUND ON THE B737-700.