I was looking for opinions on 9 bolt borg warner posi disc rears vs 10 bolt. I have both and for the 10 bolt i have an SLP Auburn unit with mosher axles. I'm going to put the 10 bolt in. But i figured i'd get some opinions from some of you guys out there

 

Well, the 9 bolts are said to be somewhat stronger than the 10 bolts, but this is really a moot point when you consider that the 9 bolt posi units are notorious for going bad, and there's no replacement options for them. The 10 bolts may be slightly weaker, but the vast availability of replacement parts for them at reasonable prices makes them a lot more sensible to use than the 9 bolts if you ask me. The 9 bolts are great when they're in working order, but when anything goes bad on them, other than bearings or seals, you're stuck scrounging for used stuff that's still in decent enough shape to replace your bad parts with. There's finally a few aftermarket ring and pinion sets available for them now in different ratios, but the price for these gear sets are insane, and you still can't buy a new posi carrier. In my book, the 9 bolt makes a good conversation piece, and that's about it. If you need something stronger than the stock 10 bolt, then it's time to pony up the cash for an aftermarket Moser 12 bolt unit. Just my .02 on the matter.

 

the 9 bolt posi carrier can be re-shimmed to OEM specs. You mill the cones, and add shims until the clearances are within spec.

 

i work at a GM Dealer and they told me today that gm has discontinued the case ,but vintage parts which is available through your dealer has them. They are quite pricey as i was told dealer cost was 746.13, but they have them in stock.