First off i know this horse has been beat to death and I've read a ton of threads on it. But I see a 50/50 split on this combo. I see people saying I have it and love it and others saying its way over geared. People say if you are towing have a lot of hills then go for it, obviously if you are going bigger tires then go for it. If you drive a lot of highway then get 4.10, you will be revving up to high with 4.56, then people say 4.0 are fine revving up high on highway. People are saying a ton of different rpm numbers driving at certain speeds. So I have a 2000 cherokee 4.0 auto with 3.55 lifted 4" on 31 duratracs and I'm never going bigger tires. I'm using the rig for hunting, so I drive at most 2 hours to hunting spots. I also use it for light wheeling, but not much. To hunting I sometimes go over the willamette pass, other spot is flat highway until hitting hunting hills. I want to know people who have my set up (4.0 auto 31's) with 4.56 gears and what Rpms are they at going 60 and going 70. I would be happy to get 4.56 gears if I know at like 65 I would be at 2500 Rpms. Thanks in advance

 

There is a gearing chart that will show you everything you want to know. I'll see if I can find it.

 

Here you go.

 

That's nice but doesn't tell you if it's for a later year auto

 

4.56 on 31's is too much gear. If you are not going to seriously wheel, stick to the 3.55, that works great with 31's.

 

you should go 4.10 if you really want to change, but a 31 is really only 30" tall so by the chart you are real close to where you want to be rpm wise w/ the 3.54 's. the auto has overdrive which will drop the rpm down some at 65 mph closer to where you want to be also, good thing bout a gear change to 4.10 is the power you get back for hills , passing & accelaration. imo 4.56 are better suited to 33 or 35's

 

Isn't that chart for manuals? AW4s have overdrive which means 4th wouldn't be a 1:1...

 

if you're truly going to stick with 31's forever then 4.10 is the right option for you. manual or automatic IMO
but the number of people who actually stay at 31's.. very low number

 

I believe you are correct. Your rpm's would be a little lower since overdrive is not 1:1

 

Well my xj now that I lifted n put 31's is a dog up any hills or towing a utility trailer with a load. So sticking with 3.55 isn't an option. Does anyone think the 4.10 is enough for driving over a pass loaded up? How about with a trailer going over a pass? Anyone with experience?

 

how heavy of a utility trailer? cherokees aren't really made to tow much more than a jetski or a bicycle and maybe some camping gear. you're not going to be doing much better than 55mph uphill no matter what gears you've got while trying to tow. you can always do 4.56's and if that's too deep pick up a set of 32's

if you're doing more towing than wheeling/camping you need a pickup truck my friend

 

I don't tow often, just was curious if 4.10 could handle it well. Not sure about how heavy the trailer is. It's metal framed, n has wood sides. Maybe 1000lbs, I should weigh it.

 

Weigh trailer figure how you will use you're rig gear accordingly .
I dont wheel as often as I like so ive compromised 31s and 4.10s getting 33s soon.

 

Do a compression test, gears won't fix a worn out engine.