mediocre69

I just installed a Rusty's 3.25" lift on my 2 door JK automatic. This netted 4" of lift on the two door. I bought JKS adjustable front lower control arms as well as rear uppers. I added 1/4" inch to the length of the front lower control arms and this netted a caster angle of about 7 degrees. It drives well with no noticeable vibrations.
The question I have is the front driveshaft on the transfer case is almost touching the outer ring of its flange mount of the driveshaft itself. I don't know the terminology of the new OEM style JK driveshaft but the angle on the transfer case side is extreme. Everything I have read said replacing the front driveshaft is optional, but I don't think it will last long at all at this angle. I adjusted the rear pinion and the rear angle really doesn't look bad at all.

spinlock

I see you are new to posting on the forum. Welcome!

Have you read the Modified FAQ?

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

mediocre69

I have seen this and the reason they recommend replacing the front driveshaft is for a torn boot from contact to the skid plate. On my '08 the boot must be farther back because I don't see a contact issue with the skid plate. Regardless I guess I will have to order a new front driveshaft right away. The angle on the rear has increased but I don't see it being severe enough to have to replace right away.

jkman77

The slip yoke boot tears on skid plate located toward the center of the shaft. You are talking about the cv joint on t-case. I had same problem. It started pushing grease out the metal band that holds boot down on shaft. Replaced mine with tom woods and no more problems . Ride is better to due to the fact that the joint was maxed out over rough roads.

joneszj

I have a 4" SUperlift on my 2 door and the stock driveshafts after 12,000 or so miles and several trips offroad. I have a 6 spd so I have a little more clearance because I don't have the skid that the auto trans does. As far as the angle going into your transfer case, believe it or not, its ok for the time being. I have flexed my suspension out quite a few times and trust me, the angle can get more extreme. It made me nervous at first but it has been holding up well for some reason. If you ever look at the side profile of my Jeep I have the control arms adjusted to their shortest setting to relieve some of the stress on the shafts. Once I can afford new shafts I can move the rear axle back about an inch and move the front forward about .5 inches or so. You should be fine driving it as your daily driver for some time. Just be aware that it could go at any time. And yours more than likely will because of the skid plate. But the angles themselves are not the most driving issue. Hope this helps some. And welcome to the forum!

jkman77

the skid plate is not the problem. what he is describing is the joint at the t-case not the slip yoke. and no he wont be fine. it can get real ugly when a joint fails on a driveshaft at on road speeds. he needs to replace it soon.

mediocre69

Yes it is the angle at the T-case I am concerned about. Since it is an automatic two door the boot on the slip part of the driveshaft is well back from the skid plate. In fact I have a couple inches between the driveshaft and the tranny skid plate but it would be a metal to metal contact there anyway since the boot is farther back on the auto.
I used adjustable control arms to correct the caster on the front axle but that increased the downward angle at the T-case even more. I would bet it will fail within a few hundred miles. I am ordering a new Tom Woods front driveshaft today. The rear angle does not look extreme at all so I will wait to replace the rear driveshaft until the summer.

spinlock

Just keep in mind a new DS with dual Cardan joints is not a panacea for all issues.

The new shaft will require aligning the pinion with the DS more closely which will likely reduce the Caster angle below its ideal setting.

I am going the same route when my stock DS begins to fail, but I've made this mod before and there is some compromise.