jeegogs : I'll try what you suggest.. dapat ba naka 4x4 pag atras?

sonny: yes I have enough gear oil.. here's what actually happens.

from 2W I switched to 4WD.. the indicator light of the front wheel and central lock blinks while the rear wheel light stays. When I switched back to 2WD and try to drive the car forward, It feels like somethings is stopping the car, parang naka handbrake.. then I can hear a "clank" sound as the wheel slowly revolves and eventually everything becomes normal..