The first thing that went wrong was the fan clutch went out and no one made a replacement for it at the time, not even the manufacturer. The problem was fixed by installing a flex-lite electric fan setup. The setup actually gave gave me better gas mileage and added power too.
The second thing that went wrong was the exhaust manifold had a crack in it. The dealership told me it was due to going off roading and submerging the engine bay in cold water while the engine was hot. The dealership offered to replace it, but I decided to replace it with the Banks Turbo exhaust and the dealership installed it for free in place of the factory one.
I bought the jeep at an Insurance Auto Auction for just shy of $2,000. The jeep is a 2004 TJ Sport. The jeep has every option on it including hardtop, full doors and 30" tire package with 16" wheels, cd/tape cd changer and 7 speaker stereo. The jeep was a light rollover, but only damaged the front driver fender and passenger side door area. It cost me about $3,000 to fix everything and change te color from silver to black cherry.
I would recommend installing a Kenne Bell Supercharger, ARB Snorkel, Banks Exhaust, Ox Lockers and a Power Programmer. The horsepower that have now is awesome, I dynoed it at 491 horsepower, I put the jeep in 4 wheel drive and can smoke off all 4 tires on dry pavement going up hill!
I would like to see your Dyno sheet. Have you done any internal mods to the motor?
I have 2004 Jeep TJ Sport. My concerns are that when you are in 4 wheel drive and want to turn, does not turn well and makes a "rubbing" sound. I also find that when shifting gears (not in 4x4, you hear a clunking sound (this sound is standard on all TJ's as I later found out). All vehicles are thirsty, but this 6 cyl is "really" thirsty, be prepared!!! Aside from those negatives, I love my Jeep and wouldn't drive anything else.
I don't believe the exhaust manifold crack is from off roading. It's a common problem with TJ's. I had a 2002 TJ that I bought new, and the exhaust manifold cracked on it. I hadn't taken it off roading in about 2 years at that time. I bet you'll meet a lot of TJ owners who's exhaust manifold cracked at some point.
Don't use 4x4 on paved roads. It was meant for offroad only or adverse weather conditions. When you're in 4x4 both front wheels are being driven and if you turn, the outside wheel needs to go faster than the inside wheel and it stresses the tires and the whole 4x4 assembly which may result in a busted transfer case very soon.
Surprised that cracking manifold is still an issue. Two pieces manifolds were used to address the problem in 1993. Too compliant trans mount seems to be responsible. The I6 block flex may also be the cause. After market manifold offer an answer.
I have about 85000km on my 2004 Jeep TJ. Only problem is the fan motor switch (on the inside) my lowest setting does not work, medium and medium high and high works fine. I had the same problem on my jeep liberty..
Not to be TOO picky here... But I will recommend you folks go check out jeepsunlimited - it's a forum for Jeeps and pretty much everybody here would benefit. To the person who said the "transfer case" would be damaged? No, it would not... The transfer case has NOTHING to do with the wheels turning in different ratio side-to-side. What you would do is break an AXLE. The transfer case has a single-shaft going into it... and to the person who posting about smoking all tires going uphill on dry pavement? Don't anybody believe that nonsense. It would take a lot more than the listed mods to achieve anywhere CLOSE to that. Like I say - pop in on any JEEP forum if you want to get real facts and get questions answered. And any 04 Jeep with just a bent up fender and door would NOT have been totalled. Perhaps this is just a "funny forum" and I missed the humor somewhere along the way.