I have a 2001 Tahoe 4x4,..when i put it in nuetrel and push into 4-hi or 4-low,..i hear a clank sound like it's engaging up front,...but it doesnt seem to be working. The back tires spin, but not the front,...and it slides around like a 2-wheel drive. The 4x4 fuse is okay. The lights switch to...