Mine has a thin flange too, like the one in this pic I found up for auction on Ebay(3.73's on torsen, but they claim an auburn). Now.. my experience in looking for the right gearset (3.42) tells me that the thick ring gear pictured is for a 2 series carrier. If the diff. assembly is correct in that photo, then slp sent me a 2 series take-off. Haven't done my swap yet, but my 2.73 open carrier flange is nearly twice as thick as my slp torsen flange. Can someone clear this up?

 

Here are a co7uple pics that should help. This is my SLp take out posi that is a 3 series carrier.

 

Here is another pic with the same posi but with some GM 3.42 gears out of a 97 LT1. They look a bit thinner than in that pic you posted.

Nothing like having a slew of rear end parts in your office.

 

Great! thanks ShiftyCapone, I was begining to think one of my parts was not compatible. Someone's definately trying to unload some parts on that auction