Have my son's 2014 compass while he's in Africa and am going to change the differential fluid I know it's 80/90 but what I can't find is quantity and if it needs friction modifier. Thanks for any help.
Run synthetic gear lube. The differential will never wear out. I use ALL synthetic in the engines and difs of the vehicles I own. Also I was a GM vette mechanic and NEVER saw a lubrication failure on any vette or car that used synthetic. Check your owners manual for the gear lube weight. Marty