My cat appears to have a nature's locking center diff...I'm not sure of the mechanics at work here, but I've got a rather amusing photo illustrating my point which I'd be happy to share with any fellow Quattro/cat lovers on request. Sorry for the silly post, Jon '87 5kSQ Jon Archibald Civil Design W&H Pacific 503.372.3616 jarchibald@whpacific.com