can i just replace parts in front differential to make my awd work again? van still runs but rear drive only.

Hi changer! The basic answer to your question is yes but it doesn't appear that you have fully diagnosed the problem yet. You need to seek professional help on this one. have someone look at it. Good luck!

I am experiencing similar problems. The problem is most likely that your front differential had ran dry, causing your pinion bearing to go bad and eventually fail completely. The fluid loss was gear oil (80/90weight oil), not tranny fluid, which is why your fluid level had not dropped. It is very difficult and time consuming to rebuild the front diff. The best thing to do is purchase a whole front differential either used or rebuilt, then un-bold old and re-bolt new. Look inside your glove box and look for the list of part numbers for your astro/safri, if gu6 is listed then you have a 3.42 gear ratio. The used part cost me $250-$300 and priced having a shop install for the same price $250-$300. (ps both rear wheels are most likely powered but only one will spin out cause the motor turns right and twists right and puts more torque to that wheel.)