94 ford ranger 4wd grinding and not disengaging

[xxtracexx]

four wheel drive makes a grinding like metal on metal noise in 4wd and doesnt want to disengage when you take it out. Any ideas what it could be? My brother is working on it and he is mechanically inclined but has never done work on 4wd he has the axle off and when you look inside there are metal or plastic "so to speak" pieces. Someone was suppose to stop by n help him out that has done it but, you would have a better chance of picking up a stack of quarters with your butt cheeks..lol so please help me out would greatly appreciate it. Its not the u-joints

 

[fiveologyjay]

Possibly the front auto locking hubs

 

[sledneck07]

same thing happend to me. i had auto hubs and they took a crap on me and wouldnt unlock. i guess that what happens when you try and pull a 25 foot 2 foot dia. oak log with auto hubs