What models of the Sport got the 3.5?
The 99 Limited has rear leafs with the 3.5l and very commonly a locker, I have yet to see a 99 Limited without the locker. Other 99 trims came with the 3.0.
2000-2001 3.5XS and the Limited have typical 2hi, 4hi, 4low t-case and the 3.5L, rear coils and higher safety levels over the 99
2002-2004(?) XS dropped. XLS and Limited have 3.5 with AWD, 4hi, 4low and aren't as durable with larger diameter tires (supposedly).
I prefer the 3.5XS models but like the 99 as well.