Ok so iv looked at the 4x4 stickys but i still cant pin the problem and the solution. When i enguage my four wheel drive the light turns on. As far as i no all 4 wheels pull but i took my truck down a sandy road to test the four wheel drive. I got myself stuck in 2 wheel and then i enguaged 4 wheel low. When i turned the wheel i got a loud clunking sound and i could feel it through the steering wheel and the gas pedal. Someone help please