hey guys i got a 2007 gmc envoy. it was stolen over a month ago and now that i have it back the rear end is getting worse and worse. it locks up and chatters really bad when turning to the left. so i pulled the cover last week and did a oil change. the oil came out black and the carrier was a black colour looked like it was a burnt residue that was just wet. so i guess i have a few questions. my first question is if i found a non g80 out of an older envoy say pre 05 would the carrier bolt in or would their be other modifications needed. my next question would be that i can get a differential out of a 2006 trailblazer ext. would this diff be an 8.6? would this rear differential bolt right in? would it change the lenght of my driveshaft and make my shaft longer and possibly bottom out in the t case? and would the u joint from my original drive shaft bolt in to the front of the ext differential housing with out having to be changed?