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Bigger gears in the XJ

Old 12-16-2010, 06:39 AM
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Default Bigger gears in the XJ

So I have been contemplating and reading on regearing my XJ, sometime this coming year.

I have a 96 4.0 HO with the AW4, 4.5" lift and 33's (currently) and stock 3.55 gears.

I had considered going to 4.10's since I thought my stock carrier would work. But now looking into parts and such it seams the stock carrier is only good up to 3.55. True?

So if this is the case and I have to change carriers to use 4.10 then I might as well step up to the 4.56 anyways right?

thanks CF.
Old 12-16-2010, 06:55 AM
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456 is the way to go with 33's

the front you will need a 3.73 and up carrier

and the back you could get away with the stock carrier. the break for a d35 is bellow 3.31 and 3.55 and above. and the break for a 8.25 is like 2.73 so you wont have anything to worry about

Last edited by N20jeep; 12-16-2010 at 06:59 AM.
Old 12-16-2010, 07:07 AM
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i went with 4:10s with 32s... it seems about perfect
Old 12-16-2010, 07:29 AM
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I was considering 4.10 if I could get away without changing carriers. since it looks like I have to change at least the front carrier.....4.56 would be the logical choice, it appears imo.
Old 12-16-2010, 11:40 AM
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Originally Posted by j-rod
I was considering 4.10 if I could get away without changing carriers. since it looks like I have to change at least the front carrier.....4.56 would be the logical choice, it appears imo.
Are you going to install a locker in the front? If you are and install a full locker you won't need to change the carrier, just buy the full locker for the 3.73 and up gear set.

The 4.56 gear set is good for 33s and great for 35s. Something people don't get sometimes is large tires have more rolling resistance and require more power and torque than the stock size so they will sometimes get better mileage with the lower gears. (numerically higher )

Last edited by Rock Toy; 12-16-2010 at 12:44 PM.
Old 12-16-2010, 12:21 PM
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x2
Do you ever have plans to go to 35's?
Old 12-16-2010, 01:00 PM
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1. i had been figuring on an Aussie for the front.

2. I may get to 35's once i replace the rear leafs and fo a couple more minor mods...but definately not as long as it is a DD. 33-34 for my DD.
Old 12-16-2010, 01:51 PM
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4.56 are on the high end for a dd if you use the highway alot you gonna being screamin in the rpm range the formula is .12x33=396 for correct gears im running 4.10 on 38s at 65 miles an hour im running around 2250 rpm great on gas
Old 12-16-2010, 02:09 PM
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Originally Posted by freegdr
4.56 are on the high end for a dd if you use the highway alot you gonna being screamin in the rpm range the formula is .12x33=396 for correct gears im running 4.10 on 38s at 65 miles an hour im running around 2250 rpm great on gas
The correct formula is:

SPEED x Gear ratio x 336 / Tire Diameter x Highest transmission gear = RPM

65mph x 4.10 x 336 / 38" x .75 = 1767 rpms

Last edited by Rock Toy; 12-16-2010 at 03:22 PM.
Old 12-16-2010, 02:19 PM
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http://www.jeep4x4center.com/jeep-tires/tire-gear-ratio-chart.htm
Old 12-16-2010, 02:20 PM
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I used this:
http://completeoffroad.com/p-3351-rp...ator-page.html

in addition to the chart you posted.
Old 12-16-2010, 02:23 PM
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with 456 at 65 and 33s your going to be running over 3000 rpm theres a chart on quadratech
Old 12-16-2010, 02:25 PM
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go down to jeep resource jeep calculators on the bottom on morris 4x4 link
Old 12-16-2010, 02:25 PM
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Originally Posted by freegdr
with 456 at 65 and 33s your going to be running over 3000 rpm theres a chart on quadratech
according to the chart you just posted id be just under 3k. I have an Auto with OD.

The below table can be used to get a rough idea on gear ratios. The colors represent ideal RPM's at highway speeds (65). These calculations are assuming a manual transmission with a 1:1 ratio. If you drive an automatic your RPMs will be slightly higher, and the opposite is true if you have overdrive (your RPMs will be slightly lower).
Old 12-16-2010, 02:30 PM
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thats alot of rpms for constant highway driving to me im standard trans

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