I have a 1993 Ford, F 350, E40D, 4x4. Got stuck in the snow the other day, locked up the hubs, tried to put the lever to 4 low 4 high, 2 high, no go,lever is stuck. Have used the 4x4 about 6-8 months ago and worked ok. Lever has always been difficult to move but always worked. Any ideas?? Please help, Tom.  

check to be sure that the linkage isn't binding up on something. it may just need a little lubricating  

This is a problem alot. The level pivots on a shoulder bolt. If you take the 4 screw that hold the boot down out and pull the matting out of the way. You with see a big 15/16 head bolt. The level rust to it. You can spray it with lube or take in out clean and never seenze it.