Im doing a large project. i went from the open diff 2.73 and im putting in a new 3.73 with a GM posi. ive got everything apart and im trying to figure out which axle seals are supposed to go in. ive gotten 3 different seals from parts stores and none of them are correct. whenever i take the old seal no one can find the correct seal. i have a 10 bolt 7.5 with drums. its a 90 RS 5.0 v8

 

Unbelievable. Most common seal of that type that there is.

It's part # 8660.

Sometimes people's stupidity surprises even ME.... oh well, no matter how stupid I think somebody can be and still not drown from standing outside in the rain looking up at the sky with their mouth open in puzzlement over what's happening, no matter how low I set the bar, they continue to fail to achieve it. Sorry all your parts store people are like that. {note to self} check that the parts counter people all have umbrellas so they won't drown in the rain...

 

I got my new seals at CQ and they where the right one's on the first try.