Differential fluid; use additive or not??

[vetterss]

I know this has been discussed and I have read the discussions but I am still not sure. I have a 2009 PPV with the G80 rear end in it and 3.73 gears. GM info lists it as a posi limited slip. So do I add the limited slip additive or not when I change the fluid? The manual calls for 89021677 synthetic which has a newer part number now but does not mention the additive. Can someone please clarify and thanks.

 

[PG01]

I know this has been discussed and I have read the discussions but I am still not sure. I have a 2009 PPV with the G80 rear end in it and 3.73 gears. GM info lists it as a posi limited slip. So do I add the limited slip additive or not when I change the fluid? The manual calls for 89021677 synthetic which has a newer part number now but does not mention the additive. Can someone please clarify and thanks.

Yes, you’re right... different info all over. At some point i read new fluid has additive in it. That said, I wouldn’t add it, drive it around... if you hear any chatter, put some in...

 

[kbuskill]

Just for the record "most" synthetic gear oils have it already in it but adding it to a rear that doesn't require it will not hurt anything.