What was found
RAISED GEAR HANDLE ALL FOUR GEAR INDICATED UNSAFE "RED" ON ALL PRIMARY AND SECONDARY INDICATIONS. CHECKED GEAR HANDLE AND FOUND TO BE OPERATIONAL BUT SLIDING HANDLE WAS GUMMED UP AND WOULD INTERMITTENTLY SLIDE INTO EITHER UP OR DOWN LOCKING POSITION. REMOVED DISPLAY UNITS NR 3 & NR 4 IAW AMM 31-61-03-2. VACUUMED AND BRUSHED LINT AND CLEANED DIRT FROM GEAR HANDLE ASSY; LUBED SLIDING HANDLE IAW AMM 32-31-00-7. COCKPIT LANDING GEAR POSITION INDICATION GOOD IAW AMM 32-61-00-5. REINSTALLED AND TESTED DISPLAY UNITS 3 & 4 IAW AMM 31-61-03-2. MEM U JACKED ACFT IAW AMM 07-11-00-2. SWUNG GEAR IAW AMM 32-31-00-5; HANDLE OPERATES NORMALLY AND ALL INDICATIONS GOOD. MEM U DOWN JACKED ACFT IAW AMM 07-11-00-2.