Front wheels locked up suddenly

SOURCE: Grinding sound in the front end

I had this problem in my 2005 F-150 twice! The first time was covered under the warranty and the second time was out of my pocket! ( close to $500.00!) There is a solodoid u[pp on the firewall that gets water into it then it corrodes the lines and such. Ford dealership replaced 2 valve assemblies, 2 actuator assemblies, and the IWE Solonoid to fix mine. They claim the problem will not come back but that remains to be seen.

SOURCE: Front differential making a winding noise and ends in a loud thump.

sounds like you need your transfer case looked at and repaired.....that the only thing i can think of...hope it helps :)

SOURCE: '95 Suzuki Sidekick 4wheel drive problem

I maybe able to help. Did it make any noise when you tried (grinding or groan hum exe..) or just not work. If so the first thing I would do is to change the transfer case oil, check for metal in the oil, if there is that's really not good, take to shop. If no shinny metal replace with good quality oil, if it's red use atf if black or brown use 75W 90 and some. Auto trans fluid is recommended in cold climates or adding torque modifier check with parts store or dealer prefferably for what to use unless comfortable with choice then change front differentail fluid, with recommended fluid and torque modifier for limited slip differentails 2oz or alittle more. both holes fill till you can stick your finger in an just bairly bend it 1/8 or so inches and touch fluid. don't try to fill all the way if it comes out of the whole your filling clean up mess and allow as much to drain out as possible. If that happens you may have it vent through the vent and may see/ smell what every you put in it. If your comfortable with taking the diff cover off and replacing the gasket if needed (usually is) make sure its clean, don't use water or anything water based brake clean is good but check for metal and brownish or simial colored stuff in bottom of housing and of course metal. The teeth on the ring gear and pinion( ring gear is the small one in the back, ring gear is big and will be closest to you. if you have hunks of metal in there its smoked and replacement of ring gear and pinion is required (not cheap) there is alot more to look for but that should start you off in the right direction.

SOURCE: Ford F150 front tires won't engage in 4 wheel drive

look on fire wall pass. side you will see 2 parts with vacume lines attached 99 percent of the time that is what went i had the same problem

SOURCE: 1990 toyota 4runner 4x4 wont lock in front wheels

your drive shaft thats turning is mabe broke or your automatic 4x4 lockers could be bad