Fellow Jeepers,

While tweaking my TJ the other day something occurred to me about the new JKs and 4"+ lifts (I run a 4.5" lift now). Does the new drive line geometry of the JKs require SYEs on 4" lifts? Here me out......

Obviously on TJs, 4"+ req'd SYEs or you would get significant vibrations. The new JKs have a longer wheel base and the rubis' Dana 44s have a higher pinion setting (slightly offset higher than midline correct?). Now, pulling a complete WAG out of my south end, here is my thought...

If the JKs drive line geometry is same/similar to a TJs with all things being equal (same pinion on 44s especially), wouldn't the new higher offset only provide more tolerance on a 4" lift. I think this might be true on a 2dr, but think about the 20" extra of wheelbase on the 4drs. One could imagine the JKs, especially the rubi 4drs, could tolerate a 4" lift without an SYE. Of course this argument is assuming the stock drive shaft has enough play in travel; if not you can always just get another drive shaft. Does anyone have thoughts on this? Have I gone off track?????? Am i just a cheap bastard who's trying to get out of an SYE???

 

I could very well be wrong but I don't think that they have a slip yoke....

 

interesting.......is the t-case setup different on the JKs? Aren't the monster lifts being offered w/ SYEs?

What do you think????

 

so..if they are fixed yoke....then all we have to do is lengthen the drive shafts to match the lifts???

haven't been under the JKs yet so appreciate the patience from those who have....

 

go to the " project-jk.com " gallery there are some under pics...

and you do know that they are using "constant velocity" joints instead of U joints right ??? totaly diff than the old stuff...

 

Listen to these guys, they know what they're talking about. The new JK's do not need an SYE and J.E. Reel is already offering beefed up drivelines with U-Joints and ones that can bolt right up to your existing flanges



Click here to see read the article on J.E. Reel Drivelines

 

no SYE kits???...thanks...I had now idea they were using CV joints and had changed the mechanicals underneath...like I said I haven't had the opportunity to get underneath one yet....definitely will save everyone money to just switch out the drive shafts vs SYE kits + drive shafts on the TJ.....

Cheers...

 

has anyone lifted their JK 4"+????? If so, what have you done w/ the ds (front/rear)?

I did not swap out the front drive shaft on my TJ and never encountered a single problem with length (the splines do show and are stretched a bit). W/ no SYE req'd, it will be nice not to crack open the t-case for a short shaft....

 

I had the same question. i wanna put a 3-3.5 inch lift on my 2dr jk what would i need just the drive shaft...?

 

You sure found an old one to revive...

If you get a shaft that will mate with your stock flanges, then that is all you will need.
If you get one with new yokes, you will have to swap out your flanges.
And with a double cardan shaft, you may need a way to adjust your pinion angles.