What about the 3.6 2012? Would I need to change any gears with 35s?

 

And a 4"lift.

 

I have the 3.8, 35's, and 3.21's. I have no problem using 6th gear (downhill). Seriously though, it's not terrible. I've been running this setup for a year and a half, not terrible, not ideal either. The 3.6 should be fine for now. Throw them on and see how you like it.

 

So the 4.10s on the 2012 should be good?

 

I have an 07 jku x with 6spd and 3.21's been running 35's now for about 6000 miles and its doable but it does kinda suck on the highway and taking off from a dead stop I have to ride the clutch a bit . I also have a CAI,catback exhaust,throttle body spacer and a superchips tuner. I am to the point I cant stand the lack of power especially driving into the mountains,even wheelin in 4lo downhill stuff sucks cause I have to go faster than I like or ride the brakes alot. I am regearing to 4.56 next week if the shop can get me in. You guys in CA. have it luck with price around here everyone quoted me 1600 to 1950 for cost to do it funny how the guy with the best reputation is 1600 so atleast I get quality for the lower price and he uses better quality gears than the others.

 

I ran them for 6 months... didn't find much of an issue with them around down... now, highway was a totally different story.

 

Exactly, and this is why they have transmissions in every vehicle.

 

Probably a dumb question, but is the 3rd brake light required? Because I'm getting a spare 35 & spent all my mod funds this month, & won't have any until next. What should I do?

 

Maybe I am missing something but isn't the OP asking if running bigger tires with stock gearing DAMAGE the eingine/transmission, not will it feel like crap to drive.

One would assume that adding bigger tires and weight would put more stress on the drivetrain and engine to work that way it is supposed to so it could cause premature wear on the eingine. By regearing, you are putting the proper gearing for the transmissiona and eingine for the setup you have so the stress is reduced.

Others might argue that it won't make any differnece on the stress on the tranny/eingine. Compare a stock JK running 3.73 gears vs 4.10. Does one Jk expect to have a shorter lift span over the other??

At least, the above is what I gethered from the OP. We all agree that regearing changes how it feels when driving but Maybe I just missed the answers on whether or not the eingine and/or tranny is compromised by not regearing when mods are done.

I honestly don;t know the answer so hopefully someone will chime in with an explanantion.

 

I'm driving the new 2012 which comes stock with 4.10 gears so I'm good on having to re-gear for a year or 2 I won't be doing much off-roading, probably light trails so that another 2