LS4 Performance - Diff fluid exchange

Well I have the opportunity so I'm doing as much to my car as I can. Unfortunately it's basically getting it to like new so that I can start with the modifications. Must take care of maintenance first.
Anyways, I was thinking and I should probably change the fluid in my diff. Has anyone done this? How much and what kind? (at work, book is outside). Pointers?

Well first, if youre posting in the LS4 section you have a 4t65-hd trans which is FWD. In a FWD trans there is no seperation between diff and trans fluid...as it all encased in the same unit. This means you will need to change trans fluid and you will be golden (Dexron IV) and DO NOT FLUSH THE TRANSMISSION, while youre at it you should also look into adding a transmission cooler which is vital to these cars...hope this sums it all up for you

Good deal. I just changed the trans fluid (no I didn't flush).
After I posted it I got to thinking that might be the case. All the products we build are fwd and some are like that and some are not.