489 case 8 3/4

[XXSpiralXX]

  Is this the one with the cone type posi? How can I tell it apart from the clutch style? ( I've never taken a rear apart before)

[Chryco Psycho]

489 Should have a cone type but it has been 30 years ... the cone type have 2 spider gears , the clutch has 4 spider gears 

[Chatt69chgr]

Clutch type has bolts around the outside of the differential opposite the ring gear.  Cone type has springs inside that you can see.  Chrysler changed over to the cone type in 1969.  There may have been some clutch types supplied in the 489 case during the transition however.  In fact, I think clutch types were occasionally used up to around 1972 or so.  Either cone or clutch type will fit in the 489 case.  Only difference is the differential bearings.

[mikepmcs]

This should help you out.

http://www.moparts.com/Tech/Archive/axle/13.html