I have recently had my fluid changed and it is still making the noise from the rear end. I was told that I may need to replace the diff.

Before I go running out to purchase a new one has anyone experienced rear noise that didn't go away with fluid change?

my vette just started to grind from the rear when im in 1st gear while not giving it gas, or when I pull out turning out of the driveway! just happens when im going really slow!

All spiral bevel gearsets whine a certain amount. And changing oil will NOT cure a whine. Only resetting the gears will help.