for all of you the 87-89 upcountry pacakges and the 88-89 limited with 4.0 had the lsd and i have a filled one with the wrong fluid once in a gmc truck it ended up toasting the clutch packs

Update time... I put the posi trac additive in this morning and all's good again Thanks again guys!

Good to hear, thanks for the update

thats real good news