Alright, I just got done with a 4" Rancho sport lift, and have 35x12.50 R15 KM2s on the way. I'm about jeep-broke for now, how long should my driveshafts last? I'd love to hear a year or so. Couple factors:
1) manual transmission
2) 7-9K miles per year
3) 95% on-road, wheeling is usually in mud, not rock crawling (less flex).
4) 2 DR Rubicon.
thanks for any input.

 

I have heard of many people with lifts and stock front shafts having a vibration due to the >3 degree pitch of the shadt to the front axle from the transfer case and causing it to crack. May want to look into it.

 

A year or so!!

Psyche...

No one can give a definite answer. Some with 4+ inches are still ok running stock shafts. Others with much lower lifts lose a shaft fairly quickly. All you can do is keep an eye open for grease spitting out. You might also want to read through a few other threads concerning that lift. There is a very long one going that has a lot of first hand experience in it.

 

Yeah, there is a long post just about the rancho 4" lift. It doesn't seem like I read of anyone having DS issues yet. But check it out, I could be wrong...

https://www.jk-forum.com/forums/show...ghlight=rancho

 

I have a 4" lift with stock driveshafts. On the front shaft the accordion boot came loose and slid back. I moved the boot back to look and there is basically no grease in there, starting to rust...will grease it up either tonight or tomorrow and just zip-tie the boot back on. As far as the boot on the actual CV joint itself...yeah it spit out some grease initially. I think they all do that anyways when a new lift is installed. It's not that they're necessarily bad or anything, but rather just the boot having to conform to the new angle squeezed some excess out. I had a mechanic look at it and he said there is still plenty of grease in there because you can feel it when you squeeze the rubber. He said not to worry about it, just keep an eye on it. I think as long as there are no actual cracks or tears in the boot to cause it to spit out grease profusely and continuously, or allow mud, dirt, etc...to get inside, then there is no need to worry. You could probably try to add more grease to the CV boot somehow (greasing needle?) but it's probably just going to squeeze itself back out again. I haven't disconnected my swaybars yet, so there's another consideration. The rear driveshaft is in perfect condition....but, alas....mine is a 4 door Unlimited.

 

I have... I had a 3" lift for a year and then moved up to the 4" rancho and ran that for a year. My front ds started spitting grease at the tcase end, so I recently dropped the $400 for a new tatton shaft... I caught it really early so I pulled the ds and ran that way for a month while i researched and had my ds built for my rig.

I do know several people w/ 4" of lift that have ran the stock rzeppa joint shaft for several years, no problem. So who knows how long yours will last. My suggestion, keep a close eye on it and to start putting money back so if it happens, you're ready.

 

So, i guess it's 'wait and see'. I read over that Rancho sport lift thread a few months back, but I'll go re-read it, thanks for the link.
I'll start building up my piggy bank for the inevitable, hopefully it doesn't happen until I'm ready!

 

You have a 2 door. Your front will probaly be okay for a while with you having a manual. I'd start saving for a new rear driveshaft, that will probaly be the first to go. The front driveshaft on 2dr or 4dr is the same and plenty of people running stock shafts up front.
The other factor is driveline vibration and pinion angles. Don't know if your JK's lift came with adjustable control arms but when you add driveshafts and change from that crappy factory design to a CV shaft you will need to be able to correct your pinion angle in the rear and correct for caster up front.

 

Keep an eye on it. This system is designed to NOT need to modify the driveshafts. But with anything that gets modified check it every oil change. I know guys who have been running the SPORT for a few years now with no problems. I think under the parameters you gave you should be in a good position to make it a year. Theo only thing that "scares" me is mud, even after a thorough cleaning it seems to always be there. LOL