cj's99xjsport

I am looking to go with 32's on my Cherokee, and would like to know what the best differential gear ratio it. Dana 45, 4.10...?

Also plan on a three inch left.

_StationWagon_

I've heard that 4.10 gears are great for 32" tires, but 4.56 work good as well.
And I think you have a Dana 35 or a Chrysler 8.25 axle.

cj's99xjsport

if i have the 8.25 , do i need to swap that? Or would that work. And what vehicle could i get the 4.10 from, and is it an easy swap?

_StationWagon_

No swap necessary. I actually had an 8.25 swapped into mine in place of the D35. I'd buy new gears ... but that's just me ...

trans_am7935

the 8.25 is a good axle, even holds up good with a locker, but if you have a good jeep junkyard near you that has a 4 cylinder 8.25 axle, you would be better off with that. the axle would cost you like $300 or so and most (if not all) the 4 bangers came with 4.10 gears from the factory. otherwise unless you know rear ends, it is a pretty expensive job to change gears. especially if you go from 3.07-4.10 cause then you have to change the carrier too!

Rock Toy

I don't think you have to change carriers on the 8.25 if you stay with the same spline count on the axles. Randy's states that they are for either 27 or 29 spline 2.56 and up.

cj's99xjsport

so if i go with 4.10 on the front and rear, will i need new carriers, and is their how to article for this. I planned on swapping differentials when i get the 3.5 inch lift. And also I have read that the 4cyl Cherokees had 4.10 in them.Is this true?

_StationWagon_

Dude ... Read the answers 2 steps above. The guy just told you ...!

xjfanatic

First of all is it a manual or automatic...If you have an automatic...go with 4.56 if you have a manual go with 4.10.

All XJs come factory with a dana 30 front end. Going from factory to anything above a 3.73 gear ratio requires a new carrier in the front.

In the rear you either have a chrysler 8.25 or dana 35.

You will not need a new carrier for the 8.25...you may for 35 (I'm not as familiar with the 35).

This is a rather intense job if your not mechanically inclined.

If you are running 32's and do not intend on going any bigger, you can get away with factory gears.

I ran 32's with a manual transmission for three years on stock gears with no major issues

just my .02

Rock Toy

Why do you think you need lower gears for an automatic?

I've wheeled all sorts of automatics and manuals, and I've always found that manual transmissions needed lower crawl ratios than automatic transmissions.

rich

Hmmm seems to be missing something (smarts)

xjfanatic

If you look at the gear ratios from factory an auto comes with 3.55 and manual with 3.07 this is due to the gear reduction taking place in the transmission. The aw4 is not geared as low as the ax15 therefore 4.56 in the axles will have a different result between auto to manual.

I'm not saying 4.10 wont work for the auto Im just saying 4.10 in a manual is about the same as 4.56 in an auto. It all depends on what his plans are for the vehicle as well.

xjfanatic

On top of that I have the ax15 manual...I put in 456 with 32s and couldn't even get up to 65mph because it was too low...slapped on some 35s and it was good to go

Rock Toy

No, 4.10 in an auto is exactly the same as 4.10 in a manual. The torque converter is what allows the automatic to use higher gears. ( numerically lower gears ) That is why a new pick up with an automatic will have a much higher towing capacity than one with a manual.

I really don't pay any attention to stock gearing because unless I know why they decided on the ratio they did, I'm just guessing that it was because they thought everyone who bought a manual did so because they wanted better gas mileage.

Rock Toy

This would have said something about the gear ratios if instead of slapping on the 35s you would have slapped in an automatic.