I believe I know the problem, since the vacuum is kicking in the 4wd will work in reverse, my front tires spin in reverse, however 4wd will not kick in forward. I dont know what could have cause this. Does that fork grab two diffrent gears for forward and reverse?, if so I think I may have stripped out the forward one, which may explain the clicking noise. Can anyone guide me in the right direction? If so where do I get this part?

I dont understand the light comes on, the 4wd kicks in I can back any where I need to go. I saw the front wheels spinning in reverse. When i put it in forward, the front tires dont spin at all, and the 4wd blinks on and off fast. Apparently the vacuum works...

 

only one gear in the front axle