• Welcome to the new NAXJA Forum! If your password does not work, please use "Forgot your password?" link on the log-in page. Please feel free to reach out to [email protected] if we can provide any assistance.

To Those Who Went From 3.55's to 4.10's

B

Big_Al

NAXJA Forum User
Location
Gaston Co. NC
I'm currently running 31" tires on my 97 Sport with 4.0 a/t and have no plans to go larger on tire size.

My question: Is there any reason that I shouldn't go to 4:11's for my rig? I use this as a dd and often drive 8hrs @ 80mph to the coast to fish on the beach where there's deep sand. (that's why I have the 3' lift and 31's on there) Not for wheeling. I read through the long sticky thread on gearing and it seems to say go to lower gears. I was just looking for some folks that had went this route before to seek there opinions. TIA....Al
 
You will turn more RPM on the highway but its not that bad.

Do this, drive the highway with the tranny in "3" if its a auto or in 4th gear if you are straight drive, that will give you a feel for how its going to drive with 4.10's. I drove my old trail rig/DD with 4.10's/31's for 2 years and liked it, my in-town mpg increased, highway mileage stayed about the same if I kept the RPM under 3k.

In my opinion, all XJ's should have come from the factory with 3.73 or 4.10 as a gearing option. You will love the extra take off power and towing power that you gain with the lower gears.
 
Last edited:
I wouldn't do it. I don't think you will even notice the difference. I did the same change on my F150 when I had it and I could barely tell the difference. Just a waste of money. I was ticked. Now, currently I am running 33's with 3.55 gears. I might regear to 4.56, but your case is just not extreme enough to need it imo. Especially since you are not wheeling it.
 
he must have meant 3rd gear
 
4.56 is usually recommended because nobody stays with 31's.... and you need 4.56 for 33's, but if you are staying with 31's.....

i run 4.56 w/ 31's, 3" and love it on the highway.
 
Is there any reason that I shouldn't go to 4:11's for my rig?
No!
Your not having any problem? Your happy with the power?
Don't fix what ant broken.
If you want some braging right? Just get a cheep shine differential cover (for show) and lie about the gear behind them. Done all the time. :)
 
Years ago, when I went from 3:55 to 4:10 on my old Ford Ranger, I noticed the change when I needed it most. Pulling a small trailer, backing up my steep driveway, pulling my boat out of the water etc etc.
I did mine when I had to do it, that is to say when I broke my ring gear and had to replace it anyway. I'm not sure if the cost of going to the 4:10 is really worth it.
But...
If you find a four cylinder Cherokee in a junk yard, they will have the four ten gears as a factory item. You could pick them up for a few hundred dollars and save the labor costs of installing the gears into your axles. Just install the entire junk yard assemblies...

Just an idea.
 
Jump This said:
Years ago, when I went from 3:55 to 4:10 on my old Ford Ranger, I noticed the change when I needed it most. Pulling a small trailer, backing up my steep driveway, pulling my boat out of the water etc etc.
I did mine when I had to do it, that is to say when I broke my ring gear and had to replace it anyway. I'm not sure if the cost of going to the 4:10 is really worth it.
But...
If you find a four cylinder Cherokee in a junk yard, they will have the four ten gears as a factory item. You could pick them up for a few hundred dollars and save the labor costs of installing the gears into your axles. Just install the entire junk yard assemblies...

Just an idea.
Click to expand...

Thats my plan! :D
 
i say go for it. even if its only a small change from 3.55 to 4.10, i think its worth it. as some have said, if brings the powertrain back to the correct final output ratio or even a little deeper. you get the power back where you really need it and dont have to "punch it" when on the highway to pass or go up an incline.

i dont know about the rest of you, but part of adding larger tires and a lift is also regearing to give you the power where/when you need it. tall gearing is fine for flat highway driving, but low gearing is great for getting around town, inclines, merging onto the highway, passing without flooring it and downshifting.....
 
I noticed a huge difference when I switched from 3.55s to 4.10s with 31"s. Takeoff power was greatly improved and now I can actually accelerate past 60 on the freeway without keeping the pedal to the floor constantly. Do it, you won't be disappointed, just be ready to turn about 2600 at 65.
 
I usually have 500 to 600 pounds of stuff in the back of the XJ. With 3.55 gears and 30" tires, the AW4 would always hunt for the correct gear when ascending inclines with the cruise control on.

I spent 9 months in 2007 working in Des Moines Iowa driving out in all directions for upto 150 miles. My MPG average about 15. I used to try to leave Iowa City going west on I-70 with my fuel tank below half. In this way, there would be less downshift on the hills.

Fast forward to now. 4.10 gears wth the same load.

Here is the RPM to MPH reading:...

RPM’s at 55 MPH with 4.10:1 gears running 30” tires 1980
RPM’s at 60 MPH with 4.10:1 gears running 30” tires 2175
RPM’s at 65 MPH with 4.10:1 gears running 30” tires 2360
RPM’s at 70 MPH with 4.10:1 gears running 30” tires 2550
RPM’s at 75 MPH with 4.10:1 gears running 30” tires 2700
RPM’s at 80 MPH with 4.10:1 gears running 30” tires 2920

Ascending those same hills now is 'Set the cruise and go home' no matter what load and fuel tank level.
My mileage is back to 20+. Of course my normal speed is 65 MPH.

I took the more expensive route and do a complete rebuild of the D44 + I wanted to add a traction enhancing device. I love the take off, the get up when I want to overtake and the ease at ascending all hills on the highway. Did I mention the fuel savings now the AW4 stays in 4th OD? (and for the tree huggers a reduced carbon foot print). After 4 years with 30" tires my question to myself is "What the F!@k took you so long?

In conclusion; If you have to climb hills or carry load, you would benefit from a lower gears. Flat road with a light load, it is your call.
 
Heh, no one ever searches. Ask anyone who has gone from 3.55's in a cherokee to 4.10s or 4.56's with bigger tires. Their first response is "why did I wait!!"

31's 4.10's
33's 4.56's
35's 4.88's

Oh, that's I-80 from Iowa City to Des Moines.
 
markw said:
Heh, no one ever searches. Ask anyone who has gone from 3.55's in a cherokee to 4.10s or 4.56's with bigger tires. Their first response is "why did I wait!!"

31's 4.10's
33's 4.56's
35's 4.88's

Oh, that's I-80 from Iowa City to Des Moines.
Click to expand...


I stand corrected. I-70 passes through Kansas City.
I lived in Kansas City then Jefferson City from 1999 to 2002.
 
I swapped 4.10s into mine with 31's. its way better than 3.55's

Highway you wont notice as much but in town is where the difference is. you are not lugging the engine as much...
 
It won't hunt in and out of 4th on hills with 4.10's.

Oh, also, if you have an AW4, put a tranny cooler on it.
 
If you find a four cylinder Cherokee in a junk yard, they will have the four ten gears as a factory item. You could pick them up for a few hundred dollars and save the labor costs of installing the gears into your axles. Just install the entire junk yard assemblies...
Click to expand...

That's exactly what I've done. I went to my local Pull-a-Part to check on a new arrival and there I found a 1999 4cly with 8.25 and D30 with 4:10 gears so they went home with me for cheap.
I just wanted to hear so opinions from those who have made the swap. Thanks for all the good replies. I have a few weeks off for Christmas, guess it'll get done soon. again thanks, Al
 
I install a LOT of gears and lockers for my friends' rigs and all of them do the exact same thing...They first want me to switch in a bit shorter (numerically higher) gears because they worry that their gas mileage will decrease if they go too short. Then, after the install, they all say they wish they would have gone ever shorter.

The shorter gears will actually help your mileage everywhere except on the highway (kind of like being in the wrong gear on a ten-speed bike, it makes a lot of work to get started or climb hills); and even on the highway, you probably won't notice much difference because of the OD on the XJ. Around town, climbing grades, and like the other guy mentioned, when you are towing or when you have a lot of gear, your rig won't be shifting in and out of OD all the time if you upgrade to the 4.10's.

That being said, a lot of people leave their 3.55's in with 31's with no complaints. It isn't a huge jump to 4:10's and may not be worth the expense it will cost you. If you were wheeling it, then I would definately say go for it, but since you are not, it's just up to you whether you want more power and better mileage in town or taller gears and lower rpm's running 80, with more cash in your wallet. Either way, you'll be just fine.

My XJ has 35's and I put in 4.56's last year. It works ok, but my mileage in town is crap and my power on hills wains. I have a set of 4.88's in the garage waiting to go in (as soon as I get some spare time). If they made 5.13's for the D-30, I would be putting them in instead.

Good luck!
 
You must log in or register to reply here.

Similar threads

Anak
How to Slot the CPS
Replies
4
Views
187
Evan03
E
M
4X4 grinding from 4H to 2H
Replies
5
Views
3K
RCP Phx
R
K
How does backspacing affect handling? 3.75 vs 4.5 backspacing for 31 x 10's?
Replies
11
Views
4K
XJEEPER
XJEEPER
M
4X4 grinding from 4H to 2H
Replies
6
Views
2K
techno1154
techno1154
K
XJ Overland build plan, need a sanity check.
Replies
16
Views
6K
jeep ride
J
Back
Top