On a 2 door this is more true then on a 4 door. On a 4 door you can get away with a 2.5 lift and the stock shaft for a long time....

 

No, the front end of the JK is the same.

You can run a 27.5" long shock and a replacement 1310 U-Joint driveshaft and not need to modify the stock exhaust.

We run JE Reel 1310 w/replacement yokes on the 2012 kits.

 

up front on a 2012, it makes no difference if you have a 2-door or a 4-door as they are the same and will have the same problem even if you just have a 2.5" lift. the problem comes from your shock length and, so long as what you have is only stock length or there abouts, you will be fine regardless if you have a 2-door or 4-door. if you have extended shocks, you will still have issues with the slip shaft boot making contact with the exhaust crossover. regarding the cv boot, it may last for a while but, it will still be in a greater state of pinch and i do have my doubts as to just how long it will last. time will tell i'm sure. in the rear, you do not have to change out the drive shaft on a 4-door but, you will want to on a 2-door as you will have drive line angle issues.

 

stock 2012 JKU here with torn boot using Teraflex 2.5"bb and stock shocks with adapters.

buy the exhaust spacers!!

 

I just put a 3" TF lift on my 2012 Rubi. Springs, shocks, Rear track bar relocation bracket, I also did the exhaust spacers. In addition to the kit I put on new TF lower control arms, new front track bar and wheel spacers. I have gone out wheeling twice and I'm amazed at what this set up can handle. The only thing I worried about is the angle of the forward drive shaft coming out of the transfer case. Can you be more specific about this statement "We run JE Reel 1310 w/replacement yokes on the 2012 kits." I am new to all this, this is my first Jeep, and my wife is about to kill me for all the money I've spent so far. The only thing that would be worse than spending more money now is being involved in some sort of emergency situation that might include tow trucks and emergency repairs. So any advice that would help me avoid that situation would be helpful.

Thanks

 

the factory drive shaft uses a rzeppa joint at the output shaft and, if you look at this carefully, you will notice that the angle of the shaft coming out of it is significant. this angle is effectively pinching the rubber cv boot and, over time, will cause it to fail. how long will it take to fail? hard to say for sure right now but, if it's anything like the 2-door rear shafts, maybe in about a year or so depending on how and what you drive on. when it starts to go, you will see grease up and long the bottom of your tub as it spits out of the boot. when you see this, you need to get a replacement right away. if you wait too long, you will start to hear a ratcheting sound coming from the joint and when that happens, you're done. needless to say, you'll be okay for a bit but, it is a problem you'll need to address sooner than later.

 

You can run the exhaust spacers and be fine. TeraFlex 3" and taller kits require the exhaust spacers/front driveshaft. Here's a video that explains it better.
http://www.youtube.com/watch?v=oKBlEpMaJC4

 

I mentioned JE Reel because thats what we use on our kits. If the driveshaft you purchase has bigger diameter shaft than a Reel, It will not clear the exhaust. I've had the pleasure of replacing stock driveshafts on the trail, its not fun.

I would rather replace the weak/prone to breaking factory shafts before I hit the trails.

 

"the factory drive shaft uses a rzeppa joint at the output shaft"
This is what was confusing me. I have been looking at after market drive shafts and not seeing the same type of joint at the transfer case. I now understand that the after market shafts use a conventional yoke and u joint coming out of the TC. Am I right on this? If so I can see how this would take care of the problem with the severer angle with the stock DS at the TC. I guess I'll be getting a new DS in the near future. Thank god money grows on trees.

 

After considering all the information I decided to go ahead with the new Coast 1310 drive shaft. It is 2" in diameter versus about 4" for the stock drive shaft. This should net me enough clearance to eliminate any exhaust contact. I ordered it today from everyones favorite vendor. He tells me they are a bit behind and it will be a couple of weeks before it can ship. Thats ok as dont see any wheelin for a couple months anyway.

Thanks for everyones input; it is greatly appriciated!