Crawl up underneath and look for any signs of leaks. While you're under there, grab the rear driveshaft twist it in both directions. You should have a small amount of play in either direction, but none if you shake it side-side. This is a quick way to check your gear wears and u-joints. Also, look under the hood for fluid leaks. Check around the exhaust manifold for leaks between it and the block. You should expect the clutch to go out around 75k, so ask about that. Another one I recently experienced is the radiator leaking at the top where the tank meets the fins. Definately want to go for the 4.0L fuel injected models. Happy hunting!
94 YJ 4", SYE, 33 mud t's on MT classics; 4.10's with Detroit Truetrac in rear