What's up guys... I'm ready to buy new gears but I can't for the life of me decide which ratio to get. I have a 2013 jku with the 3.6 and 6spd manual. Base 3.21s. Have a 3.25 inch lift, 35 inch nittos, winch bumpers, sliders all that. I drive 90% interstate daily driver and I live to go off-road when I can, camping with the kids and all... I like easy-moderate trails, not the extreme rock crawling stuff as I have to drive it to work. I want 4.56 for off road... But is 2600 rpm@70 long term bad for the engine?4.10 seems like the better road choice 2250rpm@70 but does it crawl slow enough to be enjoyable off-road ?

 

For DD and moderate trails, even with all the "irons" and full load, the 4.1 will give you plenty of power.
My heavily loaded JKU with 35"s, does hard trails with 4.1 and doesn't need more, so, for you, I think that raising the r.p.m. with 4.56, would be a waste of engine & fuel.

 

I have 4.10 gears & 35" tires with V8 and it's great for me, 2400 @ 70 MPH. I'm in the altitude and the 3.6 was a dog for me. Your in low elevation so 4.10's may be OK.

 

The highest I've driven the Jeep with the 3.6L was about 6,600 ft. There wasn't any noticeable power drop.

 

I plan on going every where in this jeep... Just want to make sure it's right. Lol I'm from out side of Memphis, I've already drive it to Moab Utah, some local parks. And headed to the smokey mountains in East Tennessee next weekend. Hince the concern for the high rpm. I also pull a small pop up camper trailer behind it. Tires actually measure 34.

 

It has a CAI and flow master exhaust if that makes and difference as well.

 

I have a 2014 JKU automatic and just upgraded my 3.21 to 4.56 on 35's and 3.5" lift. I'm also running a RIPP stage 2 SC and will probably go to 37's next. I think manual can get away with a 4.10 perhaps as a middle ground if you don't plan on going to 37 in the future.

 

If you're going to spend the money on a gear swap, you might as well get the 4.56. It will allow you to comfortably run larger tires in the future as well. Running at 2600 rpm at 70 isn't going to hurt anything, in fact you'd probably get better mpg than lugging around 2000. That said, I love my 4.88's but don't drive on the highway much.

 

4:56's will put your engine right where it wants to be at cruising speeds. This will cut down on having to constantly down shift when running up those steep hills.


Sent from my iPhone using Tapatalk . Rich

 

I don't plan on going any bigger on the tires, maybe a true sized 35 something more aggressive but that's about it until it's paid for many years from now. When I down shift it and run it at 25-2600 it feels like the engine is running really really fast...