"4.56--thats crazy!"

[JAS]

I have calculated the following


33 inch tires at 4.56 gears is witin 5% of the 27 inch tires and 3.55 gears that my jeep came with stock.

 

[xjaholic]

Why hasn't someone put a chart on here with people builds and the gears and mileage figures? I have searched and haven't made up my mind on gearing on the same issue. Someone either says 4.10's are the bare minimum and others say that 4.56 is the only way to go. The chart should have year, tranny, gears, type of mileage (city vs. hwy) what gear your XJ came with and pre and post tire size as well as lift height. Maybe then this would all help us decide which gears would be the best choice. I am looking at either staying with 32's and getting 4.10's or getting 4.56 and getting the metric equivalent to 33's. Then again, only time will tell.

 

[ChuckD]

Why hasn't someone put a chart on here with people builds and the gears and mileage figures? I have searched and haven't made up my mind on gearing on the same issue. Someone either says 4.10's are the bare minimum and others say that 4.56 is the only way to go. The chart should have year, tranny, gears, type of mileage (city vs. hwy) what gear your XJ came with and pre and post tire size as well as lift height. Maybe then this would all help us decide which gears would be the best choice. I am looking at either staying with 32's and getting 4.10's or getting 4.56 and getting the metric equivalent to 33's. Then again, only time will tell.

Sounds like you have a lot of work to do. Thanks for volunteering on this wonderful endeavor.
You better hurry on this chart I'm waitting to do my gears to! :rattle:

 

[xjaholic]

Good one Chuck....looks like you could help me with the 3K posts you have. Ha ha. I have been trying to figure out all this gearing now for 6 months. I'de like to get my mileage back as well, but I'de like to have the power it had from the factory. I guess you could also put on that the current mileage the XJ has as well. Maybe we could make a deal and I could start the chart for the small fee of some Dana 44 drum parking brake levers? It might take awhile, but I could start a sheet, then set it up here. Tell me what you guys think. Pm me if you have the data, and I'll start the sheet and it can be made into a sticky.

 

[Ed A. Stevens]

Alright everyone here says ohhh 32s, go 4.56 and dont look back you will get ur gas back and the power is awesome...then I ask 4 wheelparts and they say oh no you should do 4.11 ur gas mileage will be terrible with 32s and 4.56 unless your going to run around 35s. Broncos, Trucks, blazers, I havnt heard many of them running 4.56 unless they are going alot bigger then 32.

As you have read (it's been written), the difference between an AW4 XJ and the normal 4WPW parade of full size Broncos and Blazers is the transmission gearing. The difference is the top gear ratio; comparing the AW4's 0.72:1 (or 0.70:1 in early AW4's) overdrive to the 1:1 top trans gear common for the full size trucks.

The AW4 in OD has the XJ engine turning 72% of the rpm that the similar tired and rear geared full size truck engine turns. The XJ with 4.56 gears and the 0.72 OD ratio is turning nearly the same rpm as an older 1:1 top gear full size with a 3.23 rear gear ratio. The OD 4th gear of the AW4 helps the XJ use a deeper rear gear than the older fullsize trucks.

HTH?

 

[ChuckD]

Good one Chuck....looks like you could help me with the 3K posts you have. Ha ha. I have been trying to figure out all this gearing now for 6 months. I'de like to get my mileage back as well, but I'de like to have the power it had from the factory. I guess you could also put on that the current mileage the XJ has as well. Maybe we could make a deal and I could start the chart for the small fee of some Dana 44 drum parking brake levers? It might take awhile, but I could start a sheet, then set it up here. Tell me what you guys think. Pm me if you have the data, and I'll start the sheet and it can be made into a sticky.

I'm sorry to burst your bubble, but the XJ is a flying brick. Lifting it and adding big tires just makes it worse. you'll be lucky to gain 1-2 MPG back with the correct gearing. If you want decent mileage buy a DD beater with skinny little 13" tires, that gets over 30 on the highway.

Otherwise the only reason to re-gear is for off-road performance and reliability. With that, I advise go as low as you can with good strong axles!

 

[casm]

An axle ratio/tire size calculator may also be of some use. This one does speedometer correction, ratios for oversized tires, overall crawl ratios, and MPH/RPM estimates.

 

[OT]

Charts suck.
Take the advice of those who've been there.
Personal experience is 100 times more accurate better than any chart you'll find.

 

[xjaholic]

I'm not feeling any love here.

 

[J98cherokee]

stevens thanks for clearin that one up for me too... and ya it would be a good idea to make another chart specifically for cherokees seeing as though there are so many people that are intrested in doing this and you know they are not going to stop coming

 

[MENEZES]

I was where ur at with this decision a few months ago. Shops said 4.10s, but said 4.56s. I take personal accounts and experiences a lot more seriously than the dude at the shop. lemme tell ya, 4.56s are absolutely perfect with 33s and a 5 speed. gas mileage is decent but what do u expect from a lifted truck with extra weight and bigger tires? Trust what is being said at and you wont be dissapointed.

 

[Ivan]

Personal experience with a '98, 32's (BFG M/T), a 5 spd and 4.56's.....

It's great for my needs as a daily driver, and I've got the performance I need off road. I've driven another 5 spd like mine, but with 4.10's; and I'm really glad I went to 4.56's.

Mileage is s'ok at 14 - 18 mpg, but I understand and accept why, and the physics thereof. I have no regrets going with 4.56's....

 

[xjaholic]

I'll just start the list then,
2001 XJ 4.0 AW4 32's 6.5 lift, stock engine 3.55 gears, 14 city, 16 hwy avg.

 

[xjrrrdx]

What about my 34" trxus MTs they are like 33.5 would 4.56s be good enough to get those up and going while keeping mileage optimum given the tires?? I live in colorado and most trails need to head up through i-70 which is fairly hilly. I have the 8.25 in my 96 (29 spline) so I cant go past 4.56.

 

[Harvo]

93 Auto I-6, 4.10's and 33's. No complaints on power, the speedo is reading dead on with no adjustments, and my gas milage still sucks.

3.55 = 14.5mpg
4.10 = 13 to 15 depending on how hilly it gets on a tank.

 

[Matt98XJ]

I would agree that 4.56 would be good for 32's. I had 4.56's with my 33's and thought it was perfect. 4.56's with 35's isn't that bad, but I do wish I had 4.88's.

 

[OT]

Well, it looks to me like Four Wheel Parts is a bunch of idiot know-it-alls.

 

[ROBZ95Xj]

Well, it looks to me like Four Wheel Parts is a bunch of idiot know-it-alls.

Reminds me of a few of the peaple at my local Autozone

 

[ChuckD]

I'll just start the list then,
2001 XJ 4.0 AW4 32's 6.5 lift, stock engine 3.55 gears, 14 city, 16 hwy avg.

Did you re-adjust your speedo gear?

 

[Gojeep]

Well I was running 4.11's with 31's for years and just went up to 32's last month. Just got back from a trip and lost power on the hills and the engine had to work harder and ran hotter while towing my 4wd camper ( 750 kgs or 1650 lbs ) that I always do and even the auto ran hotter. So I have just ordered 4.56's gears!