I found an old thread about the "brown wire mod" to take out front wheel/awd via a switch. Another thread said to remove fuse 104 to do the same thing. Does doing either one for any length of time have an adverse effect on the front differential or drive components? Will doing either improve my fuel mileage? Thanks for any input/advice.

 

No and no.

The only difference between the fuse and brown wire methods is in what loses power. With the fuse, the shift motor, the front clutch, and other 4WD components lose power, with the brown wire mod, only the front clutch loses power while everything else in the system does not.