I recently bought a 2000 f150 4x4 with a 5.4 motor. The first time I tried the 4x4 I put it in neutral with foot on the brake and switched to 4L and it seemed fine. Then I proceeded to go home to my apartment which was right across the street so I switched it to 4H and then back to 2H. I noticed that when I hit the speed bumps at my apartments that the front wheels were still engaged because the tires squeaked when I hit the speed bumps. I drove around my apartments and backed up a few times and it seemed to fix itself. I haven't used the 4x4 since. I now notice a clicking sound while driving. I can't tell if it is coming from the front or rear and it isn't brake related because when I hit the brakes the sound doesn't change. I want to try the 4x4 again but I'm afraid I will mess something up.

 

doubt that you messed anything up....sometimes I too have to "back up a bit" to get mine to disengage from 4L. not to unusual to need to do that.
BTW...4L is for pretty extreme situations, 4H will more then sufficient for urban travel.

considering that this truck is "new to you"...it would be good to check the fluid level in the Transfer case and for vacuum leaks pretty sure that the front diff is vacuum activated, so with cold weather those lines can be subject to issues. Also couldn't hurt to give the front suspension a checking over, sway bar end links, tie rod ends, ball joints,shocks and U-joints.

do you have access to the former owners maintenance records...it would be good to get as much info as possible as to what was done previously?

 

Yeah I only put it in 4L to see if it worked. Weird thing is it doesn't make the clicking sound all the time. It seems to happen after I hit a bump and goes away after a while.