Jeep 4.0L with Rubicon tires (30.6") and 4.56 ok?

Wow dude, 4.56's with 30" tires is gonna be crazy to drive. I have 4.56's with 33's and it's somewhat a short gear. I usually am shifting to 3rd by the time I leave an intersection if I'm trying to be conservative about driving. I would not put those gears on with those size tires.

I also have the true track up front and a detroit in the rear, but I first had a dana35 in the rear with a truetrac and 33's, but switched to a danar44 with the detroit locker. I also had it geared to 4.11 first time, then when I switched the rear ends went to 4.56.

Now being in Florida, with really no rock climbing the 4.11's would be better for my fuel efficiency on the highway but I noticed when I was running up sandhills n such that it would bog the engine a little so I upgraded to the lower gears.

So if you are eventually going to put on the 33's and want a locker, I would say just drive it around with the 30's and no driveline mods until you can afford to do it all at once. I had the 3.07's with 31" tires and while it wasn't a strong gear I just ran the rpm's a bit higher while offroad and had no problems, even with open differentials. And don't put that locker on the dana35 rear end you probably have, a guy did this in town with 33's and broke an axle turning in a parking lot.

Troy

im running 456 with 35's 3 spd auto its perfect setup

Was that an ARB forgotten to turn off ?

Yes I do have the Dana 35 rear axle, but I belive that if I go easy on the throttle while turning I might get away without breaking my axles right?

Oh no this guy had a detroit locker and it was on a YJ, with quite a few miles on it and he's even used it heavily offroad. He said it was his fault and he should have handled it differently.

I did speak to one guy who said his son had a rockcrawler type setup on his jeep, and that the rear end had a spool. I asked how in the world did he drive it around on the roads, and he said his son put some sort of locking hubs on the rear, much like the front. Every week or so he'd unlock one wheel, so the other wheel would be propelling him so he could go around corners. He'd switch every so often to even out the tire wear.

I always thought that was a neat idea but I don't know how it would be done since I've never messed with locking hubs before. My TJ is the first offroad vehicle I've owned and it doesn't have them.

Troy

4.56s with 30" tires will be pretty low. The engine will be runing very fast at freeway speeds.

Jeff Strickland ha escrito:

According to my calculations going at

60 MPH i will be at 2650 RPM That does not sound unliveable But I really do not want to take a wrong desicion.

How often to you get to go 60? I only hit sixty on my way to 70+, then I hit it again on my way back down.

As a point of comparison, I have a '95 Bronco with a 5.8L (351 ci) motor, and I'm turning closer to 1500 at 60.

My Jeep with the 258 won't even go much faster than 3500 rpm, and that seems like a strain. I gotta think that you'll be hating life at 2650 rpm doing

60, and you'll hate 3000 rpm doing 70 even more.

If I wind my CJ7's 258 up to 3000 rpm in 4th gear, I am doing about 80 mph. At 65 mph I turn 2300 rpm in 4th and 1700 in 5th. I prefer the

2300 rpm and get a lot better mileage there than lugging along at 1700 rpm.

But I have on 33's turned by 3.31 gears.... ;-)

The red line on mine is only 4500 rpm, but at least it will pull to 4400 now, then it hits the wall. Stock with the emissions computer in the loop, it seemed to be governed to 3500 or so.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail >

The wear and tear on your engine and reduced fuel economy might be a consideration here too.

Kate

06 Rubicon

You're more likely to break an axle locked on 31's then you are open on

33's. My advice would be to get the 31's, leave the stock gears. Go to 4.56's when you get 33's and leave it open, if you want to lock it get a D44. A D35 WILL break very easily if locked.

A TJ open on 33's will wheel very well.

Carl