Sounds like the 8.25 rear end. Good axle, specially in the later years, 29 spline. Strong fro what it is and will handle 35 with a locker, the only real drawback is no aftermarket support and the deepest you can go is 4.56's. If you need deep gears, well it doesn't matter what axle you get, you'll upgrade anyways. The best year seems to be 99, newer ignition system and still HP Dana 30 and before any of that weird exhaust, 3 cat stuff. But other than that auto any year before 00, in 00 and 01 they used the 3550 manual, very very rare, but I have seen and driven a few.