Just start at the center diff and work your way to the tires to see where it is slipping. If the front center dogbone is powering the front diff then most likely you busted a outdrive pin inside the diff or broke an outdrive shaft that the pin goes into. There's plently of threads on the diff problem, and thankfully, there's a fix to it too. Most guys here have ordered the upgrade kit which contains beefed up diff pins because the stock pins can snap. Then, they temper the outdrive shafts with a torch and it looks like the diff is bulletproof after that.