I got a 2002 Ford Explorer 4.0 4x4 and i have a few questions on how my 4x4 works. Say if i got stuck while in 2x4 and i push for 4x4 wait till light turns on and then give it gas i get a loud clunk then 4x4 is engaged. Another thing is if i am already in 4x4 put in reverse to back up then put it back to drive spin my tires i get the same loud clunk. Is it suppose to come out of 4x4 once locked in? Do i have to engage 4x4 then roll a few feet for it to engage without clunk or should it be locked in once light is on? Thanks