Hey everybody..I currently have Shell Spirax gear oil in the diff. on my car, I used this because the only mineral based gear oils pep-boys had was this, and some no name brand i had never heard of. I just thought i would ask if anybody has any experience with this gear oil? Is it good? I've had it in there for about 6K miles, and when i change it i'm just wondering if there's a better choice out there as far as mineral based gear oils go. Thanks for any help.