I have a Jeep Wrangler JK Unlimited X and I wanted to put about a 3.5" lift on it (with 35" tires), if I do this will I have to replace my front drive shaft?

 

Depends on how quickly the boot at the tcase end of the shaft wears through. Some start spitting grease fairly quickly, others are good for years. There will be some variables, use and specific setup, disconnecting, short vs longer shocks, whatever else.

Crawl underneath and check the boots as part of your regular maintenance.

 

So would you think I could go ahead and lift it the jeep, just keep an eye on the drive shaft and eventually I will know if I've gotta replace it or not?

 

Yes.
This is what you watch for: grease flung about from the boot where the driveshaft meets the transfercase.







Sent from some string and a few tin cans.

 

When I put my 3" Teraflex lift on my jeep 09JKU 3-4 yrs ago my front driveshaft starting slinging grease in less then 3 months ... Replaced with a Tom Woods

 

From my research anything above 2.5 will require new ds.

 

That would be for a 2012+ due to the exhaust. The 2007-2011 have more clearance. At 3.5" of lift I would expect to do it someday. For 35" tires you would be better off with a 2-2.5" lift.

 

mine took about 9 months. Heh

Just Empty Every Pocket!

Sent from some string and a few tin cans.

 

I'm not going to even mention how long I've been on the stock shafts and no grease, cause as soon as I say anything.....

 

Shouldn't matter, facts are facts. Friend of mine had a 2.5" lift for a couple years on his two door, no problems. Put a 4" lift on and the rear driveshaft failed within 30 days. Front is still fine after two years. 2.5" lift on a four door with a six speed and my front failed after six years. It's a crapshoot based on how someone really uses their Jeep (not on how someone thinks he uses it).

EDIT:

The real question should be: Do you use your Jeep in situations where a driveshaft failing could be a serious we're-not-getting-home-today problem? If you play in off-road parks, chances are that you can get out of the rough stuff with help from a few friends, pull the failed driveshaft, and get home. If you get into remote wilderness places, chances are you're mostly in two wheel drive, so a failed driveshaft a hundred miles from help can be worked around. But, sometimes that "mostly in two wheel drive" becomes mandatory four wheel drive because the snow is deeper in the pass than it normally is this time of year, or that rain storm turned into an ice storm, etc. So, you have to decide how much risk you're willing to take on, then decide whether you're vulnerable or not. If you're like some folks with whom I travel into those remote places, you have your wife and kids with you, and your decision might be to err on the side of caution.