yes thats right

strang cus the aw4 would still have better power in OD with the same gears


a lot of the forum members have stated 3.55 with a 5 speed


any way the OP is lucky to have the ax15 its a great trany for any jeep

 

31's work with 4.10's with a manual
and 4.56's with a auto.

On a auto always go one step farther..

 

Like you said ... the converter locks/unlocks. Every little bit of extra RPM brings you higher into the torque plateau or peak (depending on your view). Realize too that the converter acts as a quasi torque multiplier.


I haven't been in this forum long enough to know what others are claiming. I'm only going off my own experiences, my manuals, my customers vehicles, and general common knowledge. I can tell you for certain about the CO altitude package because my wife & I almost bought one when we were living in CO at the time. Decided on a 97 Up Country 5 Speed that was traded in from Michigan (with 5K on the motor). Hard to beat that package.



Joe

 

I guess its all in how you look at it

did some calculations and 3.55 would bring you back to stock

this is a good sight to compare
tire and gears

http://www.rocky-road.com/calculator.html

 

That's why I said 3.55 or 3.73; Actually ... 3.31 would bring you back to stock in a perfect world. But if we account for increased rolling resistance, extra weight, extra wind resistance, dog with tongue hanging to increase aerodynamic drag, etc .... the 3.55 is the number to go for



At least we can agree to discuss civilly and let others read/learn. You other kids better be paying attention to this !





Mike37, new topic ... same time ... tomorrow night ?




Joe

 

Are you ever going to tow anything? Lower gearing will keep you in the sweet band of your torque curve. Often going to lower gearing improves your fuel mileage.
My 4.0L auto with 3:55 gears was an 11-13 mpg vehicle with 3:55's and 13.5 mpg with 4:11. Today with 4:88 gearing My XJ really came alive, towing a 3200lb travel trailer I'm getting 14.5-16.2 mpg. I'm running 31-10.50-15 tires for the record.

 

i have 31's and 3.55 gears
its atill a little slluggish so im keeping my eye out for 3.73 or 4.10

 

With the current 3.07 and 31's I get 19 mpg highway so I'm satisified with the mpg, hopfully going up a few ratios won't kill that

You brought up a good point, I do tow a trailer sometimes. Let me tell you, pulling that big trailer (about the size of a car) in the wind with that big "ramp/tailgate" folded up with 3.07 is not fun. Its pretty much just stay in 4th.

 

yes the 3.31 is the calulation match
account for increased rolling resistance +.04 = 3.36
extra weight + .04 = 3.40
extra wind resistance +.08 = 3.48
dog with tongue hanging to increase aerodynamic drag + .07= 3.55

3.55 perfect match

 

19mpg is good for a jeep

with 3.55 you should see the same as when you had stock tires

 

Funniest Freakin thing I've heard all week !!






Joe

 

Will going from 3.07 to 3.55 theoretically help or hurt gas mileage?

 

IN THEORY.... It should help. In order to accelerate at the same rate as stock you would have to apply more throttle with the larger tires, HOWEVER.... the larger tires would lower your cruising RPM's if I'm correct. I guess it all really depends on how/ where you drive. 19mpg is not bad for a jeep. Worst thing that could happen is you drop in mileage and put your stock 3.07's back in. Correct me if I'm wrong guys but don't most 4.0 / AW4 combo's have 3.55 or 3.73 gears? You could try and find a decent set at a junkyard and try to get it cheap if you're worried about having to go back. Just my $0.02... Best of luck

 

its hard to say but you should get better

what did you get before the tire change

 

Jeep had 31's when I got it, so not sure. I did some research using wikipedia and here is what I came up with what to look for in the JY. Basically bright green is good. Anyone have any amendments or see anything that looks wrong?



Looks like I need Front and rear diff from 97-99 OR
Rear D44 (if i can find it) and match it with a front D30