I think my rear-end is leeking gear fluid.i wiped the bottom of the pumkin and the fluid looks like the same color as my transmission fluid.I thought that the gear fluid is brown or black.I'm thinking of unloosen the mid area nut and check out if the fluid is low or when i'm driving that the transmission fluid is'nt driping back to the rear-end.last,what kind of fluid do i use to put in the rear axle?