Stock DS are not a problem. CV style need to be aligned.

 

So why is a new front driveshaft required at 4+" of lift? Sincere question...

 

Not 'required', but past experience from a lot of people shows that as you lift higher, the likelihood of loosing a driveshaft increases. Some with as little as 2.5" or so are losing them, and others with 4" or more are still running stockers. Just depends on the specific setup and use.

Do yourself a favor and make a habit of crawling underneath and checking the joints at both ends of both driveshafts. You are looking for grease coming out of the joints, and a ring of grease across the undercarriage above the joint.

Some considerations:
Total lift height
2door or 4door
Auto or manual
Shock length
Connected or disconnected
All onroad or max flex offroad
And the great equalizer - luck

 

yup, good advice- already doing that pretty often. I know they're not likely to last that long.

 

My understanding is that is an auto transmission issue. Has to do with interference due to oem driveshaft diameter. Aftermarket driveshafts have smaller diameter. I have a manual tranny with 4" lift. I changed the rear shaft and rotated my axle. Front is oem with no problems.

 

ah, I have a manual 2dr. I'll replace my rear DS first and see how it drives. Thanks for the note.

 

That is the big boot in the middle of the front shaft that covers the slip joint (where the two halves of the shaft slide in and out). As long as you keep it semi-clean and greased, losing that boot is not a big deal. You will notice that none of the aftermarket shafts have a boot there.

The bigger problem is if you have enough height and flex, the driveshaft may contact the corner of the tranny hard enough to split the lip on the pan. I have seen a lot of posts about ripped boots, but relatively few with damage to the corner of the tranny. Flex it and check to see how close you are.

The joints at the tcase are generally the biggest issues...

 

Do you mean that the bearing doesn't like the stock 4 degrees of caster after a lift is installed?

I put a teraflex 3 inch lift and added front lower control arms I put my caster at 3 degrees because from what I've read less caster = more pinion angle which makes the t-case and drive shaft happier.

2012
4 door
manual
3 inch teraflex lift.

 

So, how does it handle now with 3 degrees of castor?

 

Ok, now I'm worried. My front driveshaft has crapped out and I have a Coast 1310 on order. I have a 4" lift now, and I'm running around 6 degrees of caster. I was planning to take it down to 5 degrees of caster, but after reading this that still won't be enough. I have driven the JK with 4 degrees of caster, and thats not going to work. My wife drives this some, and she will be complaining if it's all over the road. I don't have the cash for a different axle, nor do I have the cash for a T-case explosion. Now I'm thinking I should go down to a 2.5" lift and ditch the 4" lift. Am I over reacting, or should I seriously consider a smaller lift?