4" lift vs. drive shafts
02-18-2014 | 06:49 AM
#12
JK Newbie
Joined: Aug 2013
Posts: 73
Likes: 0
From: Philly-Uptown
nice pics
I see you have a 2013 JKU with auto. 
The rear stock shaft has CV joints on both ends. They should not be a problem with an Unlimited.
The front may be an issue down the road. Make sure the drive shaft rubber boot is not hitting anything. On a 2013 a replacement exhaust crossover is sometimes needed. Also watch for grease splatter caused by the CV rubber seal at the front of the transfer case. As long as the angles are handled by the CV joints and not the front U-joint you should be OK. A little angle (less than 3 degrees) is OK on the front U-joint because you don't put a load on it at highway speed. Even then, it may vibrate some above 50mph.
I have a 4" Rancho Sport Lift on my 2010 Unlimited Sahara with auto and have not had any problems after 7 months.
The rear stock shaft has CV joints on both ends. They should not be a problem with an Unlimited.
The front may be an issue down the road. Make sure the drive shaft rubber boot is not hitting anything. On a 2013 a replacement exhaust crossover is sometimes needed. Also watch for grease splatter caused by the CV rubber seal at the front of the transfer case. As long as the angles are handled by the CV joints and not the front U-joint you should be OK. A little angle (less than 3 degrees) is OK on the front U-joint because you don't put a load on it at highway speed. Even then, it may vibrate some above 50mph.
I have a 4" Rancho Sport Lift on my 2010 Unlimited Sahara with auto and have not had any problems after 7 months.
02-18-2014 | 04:45 PM
#14
JK Enthusiast
Joined: Aug 2013
Posts: 408
Likes: 0
Gearing you jeep properly will allow it to shift in over drive and will in turn improve your gas mileage. If you gear to the proper ratio you will essentially return it to its stock configuration. All your doing now is putting unneeded stress on the drivetrain and engine. There is a chart online that you can find your configuration and it will tell you what gears to run. No one who has regeared their jeep properly would go back to stock gearing.
03-30-2014 | 09:41 AM
#18
JK Freak
Joined: May 2009
Posts: 998
Likes: 1
From: Enumclaw,WA
I went with a 3" lift initially so I could squeeze more life out the front drive shaft... I have a 2 door and have read that the front drive shaft is more of an issue with two doors vs 4 it worked great with 33's, when I went to 37's I replaced the drive shafts and went to 4" of lift. matthew