I'm doing a 3.5 in lift and was wondering do I need new drive shafts I do pretty moderate off roading. How long will the stock ones last me??

 

I have an AEV 3.5" Premium kit installed, have been wheeling the stock shafts all season. The flex is fine. With 35" GY MT/R Kevlars, I never even disconnect the links. I'd be nervous about the shafts if I did, but it handles everything I've thrown at it so far. I did tear the spline boot on the front shaft, they can't be replaced without buying a whole new shaft ($^%Chrysler). I just keep it greased & it's fine.

 

1) If you have a 4 door 6speed, no you dont need drive shaft
2) if you have a 4 door automatic, yes you only need the front drive shaft
3) if you have a 2 door, yes you only need the rear drive shaft

You can run 3.5'' with stock driveshaft, but dont hit the trail before changing the stock driveshaft, in the pavement you will be ok.

 

I have a 6speed 2door

 

Too many variables to say for sure, but with a 2door at 3.5", you should go ahead and plan on replacing both eventually. Keep an eye out for grease splatter and drive until you need to replace one or both.

Some considerations:
Total lift height - not mfg's listed spec.
Shock length - longer shocks let the axles droop more.
Disconnected or not - lets the axle droop more.
2door - that rear shaft is very short.
Use - onroad is less likely to need shafts than flexing offroad.
Transmission - auto's have more issues, but front shafts on 6spds can contact the exhaust.
Luck - regardless of any other factor, the shafts will be operating at steeper angles. The small boots in the joints can and will wear through eventually even if you never go offroad.