I have a 98 xj with 33s. I get about 200 miles to the tank I don't feel like thats very good. I am running stock gears for now. I have dont some searches and it looks like everyone is running 4.56 gears with 33s. When I change my gears to the 456s should I expect a good noticable differents in power and MPG?

 

you should see a gain in low end power but i think you'll see a decrease in milage based in higher rpm's to make highway speeds. correct me if im wrong here anyone.

 

I sure hope not!! When I am driving down the road at 55 or 60 I have to down shift all the time to keep it to speed and I have to use alot of gas all the time to keep it to speed. Taking off it has OK power getting up to speed its just keeping it there.

 

did you compensate the milage for the larger tire size?

probably more around 230 miles.

im stock on 33's with 226k miles on a tired 4.0 and get about 16-17 mpg

 

higher rpms doesnt mean worse gas milage

its actually better to keep the engine in the power curve than lugging it

especially with an auto.

when you are constantly having to shift and slip the torque converter to get up hills and to accelerate milage suffers greatly

i have run 5.38's on 35's-37's and was able to get low 20's on the highway

 

I think you will get better gas milage because the engine isnt having to work as hard. But i will let you know. I am putting 4.56 gears in my 2000 xj in this week unless family has better plans for me.

 

that is an odd problem. keeping it up to speed? are you loosing rpms?

 

I run 4.56 gears with 33" tires and even with lockers front and rear I get 18.5 mpg on the hwy. That was on a trip to Nevada and back just a couple weeks ago.

 

That comes out to between 300 and 325 miles to a tank.

 

i see what you're saying KTM, makes sense. larger tires need more rotation to make ground speeds. hense the higher gear ratio. but the constant shifting? up and down hills? flat road?

 

i have 33's with stock gears now

and anytime i come to a hill on the highway my rpms jump and i go nowhere fast

due to the torque converter slipping trying to keep the engine from lugging

 

so if ruttenit goes to 456's he should see an increase in milage. i dont worry so much about that stuff as my rig gets a free trailer ride.

 

definately

i prefer 4.88's for 33's, but both are a good investment

 

How does your jeep run and what kind of milage and rpms are you getting with 4.88s around 65-70 mph on the hwy? You realy got me wondering about 4.88s VS 4.56s


As for an earlier question, It does loose rpm on the hwy and it always has to down shift to keep it going at 55 or 60. It feels like the tranny is working to death and I am afraid to drive it in overdrive