Landing gear without engines

[KGSZ]

I updated my sim to su4 and my plane to 1.18 and i want to try some extreme things like dual engine failure. After failure i turned back to approach KLAX 7L but my landing gear lever and l/g gravity extension wont work. I downed the lever but gear doors dont opened after this i think i should use gravity gear extension but in down mode it didnt do anything. But reset mode downs gears. Am i doing something wrong