After almost 1/4 million miles on my old 2005 Chevy Avalanche 2WD Z66, the G80 Gov-Loc diff started to get noisy. After pricing a rebuild, I decided to go with a used diff from a ‘reclamation yard’. GM used these diffs in a zillion vehicles and the first yard I called had one out of a 2005 Tahoe. I took my title with me so the yard could decifer the Vin number and it was an exact replacement. Problem is the yard said they didn’t know the mileage because they didn’t have a key for the donor vehicle… 
. I did get an estimate from a reputable rebuild shop for $3,000 to $3,500 excluding taxes.
I didn’t want to put 3K minimum into a 19 year old truck and more than likely it wouldn’t even sell with a bad noisy diff. The yard did offer a 90 day unlimited mileage warranty so I took a leap of faith and bought it for $600. My father and son shop said they could replace it tomorrow for $600 labor. It has virtually no rust and almost new looking rotors on it and my shop said they would move my calipers and almost new pads over to the new diff. So for roughly $1,200 VS possibly $3,500 and a 90 day warranty I’m taking a chance but
maybe I’ll get lucky. This old truck drives, runs, rides and looks great so I’m probably somewhat biased and with truck prices through the roof. What would you guys do in my situation? Also, I had Delvac1 non LS in my old diff for the last 50,000 miles but open to suggestions in this ‘new’ one. I do have a few qts of NAPA 75w90 with LS additive on the shelf but I’m a bit shy about using it in a non LS diff.
. I did get an estimate from a reputable rebuild shop for $3,000 to $3,500 excluding taxes. I didn’t want to put 3K minimum into a 19 year old truck and more than likely it wouldn’t even sell with a bad noisy diff. The yard did offer a 90 day unlimited mileage warranty so I took a leap of faith and bought it for $600. My father and son shop said they could replace it tomorrow for $600 labor. It has virtually no rust and almost new looking rotors on it and my shop said they would move my calipers and almost new pads over to the new diff. So for roughly $1,200 VS possibly $3,500 and a 90 day warranty I’m taking a chance butmaybe I’ll get lucky. This old truck drives, runs, rides and looks great so I’m probably somewhat biased and with truck prices through the roof. What would you guys do in my situation? Also, I had Delvac1 non LS in my old diff for the last 50,000 miles but open to suggestions in this ‘new’ one. I do have a few qts of NAPA 75w90 with LS additive on the shelf but I’m a bit shy about using it in a non LS diff.
