well, i opened up my rearend today, i didnt completely drain it, or inspect it, but the oil was grayish and real sludgy, and i felt alot of metal shavings on the inside on the bottom, boy that gear oil stinks!!...it doesnt matter if its toast or not, because i`m still puttin the posi in, it would actually be better if it werent, but from the what i could see, the gears looked ok besides the metal shavings, but i really havent a clue, one thing i notice while i was under there was that it looks like gear oil was coming out of the diff vent tube, as it was all over the place where the outlet of the tube is, and on the gas tank skid pan, i just threw the cover back on because i couldnt stand the smell......just letn you know what i did/found....think it mightve been grindin, well it almost sounded like a wind up toy, except different, if that makes sense, and when i would slow down it would make the noise again and then a clunk, and it only made it (while over 45 or so) while i had my foot on the pedal, but when i was goin 30 it would do it when i slowed down a little, or even let off the pedal for like 15 or 30 seconds