Hello, new member here. First post. I’m about to install a RC 4” lift and add 35’s (moving up from 33’s and 2.5” lift) on my wife’s 2017 JKU Sahara, and the notes on the site say that at full flex, it’s possible for the stock driveshaft to make contact with the oil pan (I think it was), and that it may be necessary to purchase an aftermarket smaller diameter front driveshaft. I went through every review that I could find, and I don’t think anyone mentioned replacing their front driveshaft. We wheel pretty regularly, but I’ve never disconnected the front anti-sway bars. I’m curious to know if said contact is likely without disconnecting those sway bars. Sorry if his has been addressed before, maybe someone can direct me. Thanks.

 

Well, you're not asking about lift so I'll not say much about it, but if that thing comes with a drop pitman arm I'd refrain from installing it. Instead keep the factory pitman arm and use a flipped drag link in combination with a raised TB bracket on the axle as the "high steer" kit/correction. Drop pitman arms are a major headache on our JKs and RC is notorious for them.

Anyhow, at that lift height your DS is going to be a ticking time bomb regardless of clearance. The CV joint at the TC side can't handle the angle. It will rip the boot, spew the grease, dry out and die. You'll see the signs and hear the clicking. You might get some life out of it but that will be the eventual death. Just budget for a DS and maybe you can find a sale around a holiday. It's definitely not an urgent matter. The clearance issue will likely be with your exhaust crossover. Using spacers is a bandaid solution. You could also re-route the crossover to behind the cross-member with a y-pipe or a custom mom & pop muffler shop job for cheap.

Welcome to JKF btw. I get out that way a couple times a year to hit BMRA/Gilmer.

 

As noted, the driveshaft is something to watch, not a definite. It can depend on use, lift height, disconnecting, and just plain ole luck. There's a chance that it will be fine, but do some reading on exhaust spacers, touch base with an exhaust shop on rerouting, and also form an opinion for what you want to do if/when that joint starts spitting grease. (a high angle joint replacement may work instead of a new shaft, depending)

Have you considered keeping your current 2.5" lift and swapping to flat flares? What is the current rim backspacing? (if stock, are you swapping to lower backspaced rims, or adding adapters?)

Which version of that RC 4" lift are you looking at? Guessing the $500 version that includes the Drop Pitman and Cam Bolts? Just a friendly suggestion, but look past the low-low price tag!! Re-read the comments above, then do yourself a favor and search for more feedback on drop pitmans and cam bolts (they may be perfectly fine for your needs, but understand what you are getting...) There are also plenty of previous posts on this site from owners of that lift asking how to correct their new driveability issues - might be worth some time to read through a few.