Stupid question, maybe, but how do you tell a cone from a clutch without opening up the diff? I have a pair of 489's in 3.55 and 3.91, both Sure Grip. Is there a way to tell without 'carving the pumpkin'?
If the center section is out look at the suregrip. The Auburn cone type will have springs visible, the clutch type will be more of a solid case bolted together.