my 1990's rear diff has a tag on it that says to use only limited slip oil only. i read somewhere that they came factory with detroit track-lock limited slips. does mine have that?

my 1990's rear diff has a tag on it that says to use only limited slip oil only. i read somewhere that they came factory with detroit track-lock limited slips. does mine have that?

It sounds like you do have a Trac Lok limited slip. You have to add a friction modifier to the gear oil so the clutches will grab correctly.
BTW, Detroit doesnt make Trac Lok, Dana does.

oh yeah, dana, thats what i meant.