Engine rear main seal leaks oil, which is a common fault with the straight six, and was cured by using high mileage engine oil (which has an additive that causes rubber to swell).
Self adjuster cable broke in one of my rear brake drums, and the cable wrapped around the brake pad, which caused a large groove to form in the drum itself. I would attribute that to bad dealer service though. The one time I took it to a Jeep dealer.
Nothing catastrophic has ever happened to this vehicle (at least not while I've owned it). It has covered 94% of the distance between earth and the moon (approximately 360,000Km), and I fully expect it to reach the moon and start coming back without so much as an engine rebuild.
I would have to say that this Jeep has been the best purchase I've ever made. It is rugged enough to take off road up a trail that is normally only wide enough for quads, and tow a trailer full of waterlogged lumber over hilly roads (though not at the same time), yet comfortable enough to drive for hours on end.
The best part about the car has to be the engine. If you look up torque in the dictionary, you will see a picture of this 4.0 litre straight 6. It's powerful enough that I regularly pass newer cars going up steep hills on the highway, while I'm in 5th gear. Having said that, the engine does lack a bit of high end power, given all the low end torque it possesses, but hey, you can't have your cake and eat it too.
The reason I said I wouldn't buy another car from this manufacturer is because, in recent years, Jeep has become too Chrysler-ized. The 1991-2000 era, shortly after Chrysler bought Jeep from AMC is the time when Jeep vehicles were at their best. The cars were AMC designs that had been improved by Chrysler engineers, and the collaboration proved to be great. From about 2001 onwards, Chrysler replaced the old AMC designs with their own, and that's when people started to experience the typical Chrysler problems.
Also, I love the shift-on-the-fly 4x4. It's really convenient when you just need a little extra traction to start on an icy road, or any time when you only need 4-wheel drive for just a second, and don't want to get out of the car to lock the wheel hubs.
Once again, this has been the best buy I have ever made, though it could be better in the fuel-consumption area. I get about 13mpg (30L/100Km) city and 27-30mpg (7-9L/100Km)highway.