Originally Posted by ChrisSlicks

I changed mine at about the same mark to put something in them better for the track. The oil from the transmission came out looking like new, the oil from the diff was dark and dirty and the drain magnet was covered in metallic sludge. So if you drive with high diff temperatures I would change the diff fluid every other oil change until it started looking better. The first change is always going to look the worst because of break in.