I have a 1998 GMC Envoy (Jimmy) and I have been tracking down a 4wd issue for the past couple of days. Found that the transfer case vacuum switch was leaking fluid into the lines. Replaced the switch, drained the excess fluid from the Tcase, and cleaned out the lines. I now have good vacuum and my actuator under the battery is pulling the cable tight but the 4wd is still not engaging. after more searching I believe that the gears inside the diff are ground off as I heard a clicking grinding noise when trying to use 4wd the other day. Anyway, I am looking for those gears. should I just go to the pick n pull or is there an online source that sells them. Thank you in advance.