My buddy just got a TJ and wants me to teach him the laws of the land. Only problem is I only know about JK's lol

Tell me what I need to know to make him a better jeeper!

 

Bump to the previous TJ owners!

 

Axles? What are they susceptible to? Gears?

 

You don't give too many clues about what TJ it is, and what he needs to know depends a lot on the year and model. If it's a Rubicon then the axles are Dana 44s and should be more than adequate for mild off-roading and anything else on the road. Every other TJ came with a Dana 30 up front and a Dana 35 in the back. These axles were good for every day but are really not strong enough for anything but the easiest off-road duty. Like every other Jeep, the axle fluid needs to be changed every 15,000 miles to keep them in good shape.

Other than that the TJ's I've had (currently a 2006) have a lot of the same problems. My 2000 TJ 5-speed blew the transmission throwout bearing after only 13,000 miles, so be careful there. If it's an automatic, the clip between the transmission linkage and the transmission arm tends to break easily so always use the emergency brake when parking to avoid having to force it out of park. The engines tend to develop front and rear main seal leaks fairly often, so if it has too many miles on it be careful if you switch to synthetic oil as this can make leaks worse. And like every other Wrangler, TJs are susceptible to death wobble if the front end isn't tight or they're lifted too much.

 

TJ's had two rear axle options, the Dana 35 and the Dana 44. The 35 is a piece of crap and is easily identified by the rubber fill plug on the differential cover. If he's gonna lift it I suggest getting a slip yoke eliminator kit regardless of how much he lifts it, and buy a quality lift with adjustable upper/lower control arms. The dana 30 front doesn't have locking hubs so if he decides to put a traction-aid in there I'd suggest something selectable like an ARB. I had a tru-trac in the front of my old TJ (I think) and it worked great like 90% of the time. The other 10% is when it would slip and transfer all the power to the other wheel. Their is a problem with the heater control panels shorting out, there was a write-up in JP about it earlier this year. I had that problem with my TJ as well as with the blend door. Other than that I never had any issues out of my TJ. I beat on it at Harlin, Kentucky and Morris Mountain, Alabama and it never left me stranded. All I had was D30/D44, 4" Rough Country w/ fully adjustable upper and lowers front/rear. 4.56 gears and Detroits (full detroit in rear), 1" aluminum body lift, and 35" tires. Oh yeah and when I did the slip yoke eliminator kit I did replace the chain, it was only about $60.00

 

Rule and bylaw number #1 WAVE TO ALL WRANGLERS YOU SEE ON THE ROAD! Don't hesitate to wave ever.. Just make it a habit to wave everytime.. Be the 1st to wave everytime and the rest will fall into place.
2nd go to nearby jeep rally's , rides, look into local jeep clubs in your area.
3rd Have fun. No matter what jeep you own it's all just a matter of SMILES PER GALLON!!

 

My dad has an 02 and my brother has a 97. I have become very familiar with them as I am the only mechanic in the family. Just a couple of highlights:

-Fuel injectors in the 4.0l tend to stop misting and start squirting. Pickup a decent set from Precisionautoinjectors.com
-The rear shocks tend to pop off the bushing and start to rattle against the frame. Invest in a shock pin eliminator kit.
-The sway bar bushings tend to wear out and it migrates one way or the other and ends up cutting a groove in the frame rail right where the sway bar link mount to the sway bar. Just keep an eye on it.
-Oil leaks from everywhere. Oil pan gasket, rear/front main seals, timing cover gasket, valve cover gasket, and depending on the year it could have an oil filter adapter gasket. I have always been told that if the rear main isn't leaking you are out of oil. I believe 1qt between changes is considered normal.
-The fan clutch tends to lock up or tighten up and it will make the motor loud and sluggish. Best advice is to get rid of it and use a dual electric. Helps with water crossings also.

Give me a bit and I can probably think of more but these are just problems I have seen in both my dad's and my brother's as well as a few friends jeeps along the way.

Have fun.

 

Don't ever get an electric fan for the mighty 4.0L. The stock fan clutch MAY seize on you but it's not very often and it's cheap and easy to fix if it does. In considerable heat, an electric fan just doesn't cool the engine as well as the stock cooling system can. If you DO have a cooling issue with the TJ, it's simply because something is broken. Many a debate has been had on this subject and the outcome is always the same: Keep stock cooling system.

-If you ever have an O2 sensor go bad; ALWAYS replace it with a MOPAR sensor as the computer HATES any other brand. (ask me how I know)

Honestly, just have him go to *********. It has TONS of info for TJ's. Anything that goes wrong with his Jeep has been covered on that forum at least twice.