Did a search on this but didn't get a real clear answer. I just looked at my RPO codes and discovered I have a GU6 (Rear Axle 3.42) and G80 (Positraction / Limited Slip / Locking Rear Diff). Is this a good setup??? Also, how does an "open" diff play into all of this??? Does this setup (RPO codes) apply to the front axle as well??? Also, I just changed out my rear diff fluid a while back with 80-90W Valvoline Synthetic Blend. Should I have used this tube of special additive I keep reading about??? Sorry for the load of questions ... just trying to learn more about this stuff. Thanks in advance!