I have a 08 unlimited sahara and have been considering lifting it and putting 35's under it but have some questions and concerns! i am looking at rough country's 3.25" lift or maybe the 4" but im concerned about driveshaft issues and gearing as well! if i could get opinions on some people with a four inch lift that would be awesome so i can finally do something with it! Thanks

 

I believe with either of those lifts, you'll potentially hit the front drive shaft against the transmission and tear the boot.

 

What gears are you running now? Auto or manual? Anything worse than 3.73 + auto I think you will hate yourself. 4.10 + auto is tolerable with 35's but still not great. 4.10 + manual, or better, I wouldnt pay the money to regear. Now that advise is for streat driving. If you are big into rock crawling (prob not in Georgia?) then lower gears are way beneficial. Especially with the Sahara transfer case. A Rubi 4:1 helps make up the difference there.

Driveshafts arent as critical on the 4dr as the 2dr... but still a little bit of an issue. If you have 3" or more (and sometimes less) and its really flexy (heims, smaller bumpstops, etc) there is a good chance you will rub the tranny pan with the front DS. This will tear the dust boot, but that really isnt that big of a deal. I think mine was off for about 20k miles with no issues. The real prob is with the zep joint on the DS. WHEN that tears from the steeper angle, it will throw its grease and the joint will start to wear down. You can run your front axle a little off center to the drivers side (barely) and make it so you hardly ever rub the pan. If/when you do, its not typically enough to jack up your pan. The bigger concern is breaking the seal on the tranny pan and causing a leak than messing up your DS. That has happened to me twice now. The GOOD thing about the OEM front DS is that it can handle more caster/pinion than your aftermarket double carden joint DS's. You can tyipcally run 6*+ caster before you get much DS vibes. With your aftermarket DS's you TYPICALLY cant run as high. In some cases guys cant go much over 3*. The rear isnt really an issue at all in those height ranges.

There is a lot more info on the topics, but I hope this much helps get you started...

 

Are you still just in the overwhelmed info gathering phase, or do you have specific questions?

Start with the FAQ's...

https://www.jk-forum.com/forums/modified-jk-tech-2/modified-tech-faq-answers-questions-every-newbie-has-18617/

Great info for these questions in the Wheels & Tires, Suspension, and Axles Gears & Drivetrain sections.

Then do a quick search. There are several RC threads in just the past week which will give more info on those kits. (as well as some feedback on included components and some recommendations on extra items)

 

I have a '08 Rubicon Unlimited. Running the Clayton 4.5" lift with 37s. I installed the lift without installing new drive shafts at the same time because of time constraints. I figured that I would do it shortly thereafter, but now I am going to wait to replace them until I have to. Maybe not the right approach, but the one I am taking. I have over 10,000 miles since the lift, and spend each weekend on the trails, and no issues - as of yet. Everything is still in order. I check constantly just to make sure. That doesn't mean that it will work for you. I guess it just means I am lucky or don't regularly flex enough to where I get contact and something can get messed up. If you have the cash on hand, I would go ahead and switch out when you do the lift, if not, I would think you would be good for a while, maybe even forever. Who knows. I think a lot depends on your vehicle and how you use it.

 

I have Rubi, 4" lift and 35's. If you have auto you will want to regear to 5.13's at a min. The rear driveshaft will be OK, the front will be OK unless you wheel it, in which case it will eventually hit the tranny pan and tear the boot. (mine finally took a dump in Moab). BUT as long as it has warranty just keep replacing the front shaft on them like I do.

 

4 door 35's 4:88's
4" superlift
no drive train issues at all
77k miles

 

to run 35's, 3" of lift is more than adequate and it's what i'm running on my orange JK now. as far as drive shafts go, if you have an auto, you will end up tearing the spline shaft boot for sure the first time you go wheeling and the only real fix for this is to get an aftermarket replacement shaft as they are narrower in diameter and will not have this problem. being that you have a 4-door, you will be fine with your factory rear shaft especially if you stick with a 3" lift. as far as gears go, i have 3.73's and they seem to do the job just fine. of course, running 4.88's would give you a bit more pep and 5.13's even more so but, i haven't seen the need for them.

 

I'm running a 4" on my 4-door (probably a bit much). I tore the boot on the first trip after the lift. I'm now running a Woods DS and haven't had any problems since. I'm running an auto trans with 4.10 gears. I'm currently running 33x12.5 but am getting ready for 35x12.5. I don't have any issues currently with traveling down the road. It has enough pep for me and handles well offroad.

 

Your front DS will be the sticking point with a 4" lift. The boot will tear sooner or later, but that ain't no big deal. It'll still last a decent amount of time with a torn boot. Like WOL stated, the only real solution for that is an aftermarket DS, I finally went that route with a Tom Woods.

If you have an auto, the stock gearing is gonna blow. Got 5.13s now and its nice, but by no means over geared.

Final point, After the 4" lift, I added 3/4 spring spacers to get a little more lift and that was the breaking point for DS vibration. I started getting alot of noise as the pinion was pointed horizontal and the DS was connected to it at too steep an angle. I have lower adjustable control arms and so I shortened them up all the way to pitch the pinion up, and it helped, but it still made noise at fwy speeds. Thought it might be the t-case bearings, but it wasn't. I needed to pitch the pinion up even more.

I was sick of buying stuff and didn't want to drop the $300 on upper control arms so I took em off, cut em and made them about 1/4" longer. Big difference, no more vibration from the front DS. Ohhh, and $10 in steel. Had to stem the cash loss . . . if only for a bit.