tnt008

I noticed many times reading on this forum, that people say if you lift your Jeep over 3", you need to replace the front drive shaft. But is this just for the 2 door or both 2 and 4 door?
If the answer is just a 2 door, my next question is is how high can you lift a 4 door before you run into issues with the front drive shaft.

c17loadmaster

4 inch and you can keep the stock driveshafts. The driveshafts aren't really the issue, yet it is the pinion angles. If you lift it and have the coil spring perches cut off and moved ( to line up the pinion) that works too. You only need to do that with more than 4 inches of lift. If you plan on running more than 37's you'll want a 6 inch lift. Hope this helps.

Beau

Front Drive Shaft
With an automatic (2 or 4 door) there is a very good chance that your front driveshaft will come into contact with your front skid plate while flexing. Mine did with only 2.5" lift. It tore the boot that covers the slip joint. During the same trip the DS also starting to throw grease at the Transfer case joint. When I got home I removed the DS and bought a new one. You don't want that to seize up. Even with a manual, you can cause the Transfer case joint to fail from wheeling.

Rear Drivshaft
On a two door, the angle of the DS on the transfer case gets really steep when you lift it 3" or so and will cause that Transfer Case joint to throw grease. I was running a 2.5" coil with a 3/4 spacer and mine is still fine. I do have rear upper adjustable control arms thought which may help. I just installed a taller lift and I know it will only be a matter of time before the rear DS goes too. I have the replacement sitting in my garage. Both are Coast double cardian 1310s.

So, 2door automatics are the most susceptible to stock DS damage, but it can happen to any JK.

phantom lord

i think my front is going south because, i noticed that at the transfer case side alittle grease was oozing out under metal clamp. well, it's been at least a month since that was going on. It has now stopped? now it seems that my u joint is throwing grease because, i found tiny little specs on my oil pan and front lower arms. i have a 3" lift and manual trans. i hope it will last til october? what else will i need besides a new shaft to get this correctly installed?
thanks for any advice.

mkjeep

Umm, not necessarily.
FAQ-
Q: What are all the components that I will need with a 4" lift?
A: For a 4" lift, you should have a set of 4" coils, bump stop extensions, longer shocks, extended brake lines, longer sway bar links, adjustable front track bar, adjustable rear track bar, front and rear track bar relocation brackets, dropped pitman arm, adjustable upper and lower control arms front and rear and new double cardin u-joint style drive shafts.

On a 2012-Up, you will want to install a new front drive shaft regardless if you have an automatic or manual transmission. Assuming you install new, longer shocks with your lift, the extra droop you will see at a flex will cause the slip shaft boot on the drive shaft to tear. However, that is just one problem you will encounter. Even if you install exhaust spacers or relocate the cross over, the CV boot at the output shaft will be sitting at a significant state of pinch and this will cause it to fail prematurely.

I should add that on a 4dr auto, you can get away with running the rear stocker for quite awhile as long as you dont bash it into something.