i have a 2000 2dr 4.3L and i had to swap outmy front dif. I got a good condition one from the junk yard . yes same gear pattern. I also completely re-did the whole front end i'm talking hubs and cv axles. My problem lies with the fact that when i put it in 4 wheel i hear the transfer case engage but my 4x4 doesnt kick in, i'm thinkin vacuum actuator but i'm not sure any feed back?

 

i figured out that it was the vacuum actuator button that wasn't catching the shift cable works like a dream now