I'm going from memory here, and getting older, so memory is not what it used to be, but disclaimer aside, I think on a 2000 with the system in good condition you should be fine - earlier vehicles had problems with the dog clutches slipping under heavy loads, and I believe the assembly were redesigned within the first year or so - you'll know soon enough if yours is problematic, you'll hear a metallic bang if/when it slips - I don't think the 4x4 usage you have envisioned will put too much stress on it.