I own a 1993 YJ 4.0 with the original dana 30 and I have recently installed the Aussie Locker in the front. The vacuum system works intermittently at best. I have decided because of the age of the vehicle that i will just upgrade to a single axle. Is this something I can buy off the shelf or does it have to come out of salvage. I have seen people mention TJ axle, is that the best route?