anyone running these?? i have 3.73 right now and while its not THAT bad i want to upgrade soon. i have 3in and 35's. manual tranny. i was thinking of trying to find some 4.10's but dont wanna throw some used gears in my jeep. how are the 4.56 gears? i am just looking for a little more power on the highway, sixth gear would be nice and possibly a little more gas mileage. any opinions??

 

I got the same question... and I have an auto.

 

Woods is running them with 33" tires. Most with 35's including myself are running 5.13's and I like them. The gas millage drops a lot. I am 10.5 to 12 city and 13-14 Highway.

If gas is a concern most then go with 4.88's and tend to like them. Not as much get up and go as the 5.13's. 4.88's is more like stock.

 

maybe 4.88's is the way to go then. hey sgt evil, you a marine??

 

I have the KM2 35s and a manual. I had 4.10s (terrible). I went with the 4.88s and love them. I would imagine the 5.13s would really add pickup.

 

New 4.10's can be found moparpartsamerica. But IMO not worth the time and money.
4.56 should gain you 'round 500 rpm... lets say at 65 in high gear your cruising 'round 2300 rpm,
4.56 bumps up to round 2800. ( Sounds just right to me )
IMO 5.13's way to low for a 6 speed daily driver.

 

I have 3.73s and was thinking of going to 4.10s. I run 33s and at 60 mph the engine seems lug down a bit. i just want to bring the rpms up a few hundred. Would 4.10 do it or should I bite the bullet and get the 4.88s?

 

If you want to know the change in gears from current to a potential new diff gearing ratio....just divide the old by the new to get the percentage change.

For example, if you have 3.73's, and are considering 4.10's:

3.73/4.10 = 0.9097

This yields ~ 9% change

Take your 9% change, and simply add 9% to the rpm's you are at in any gear now, and that's ~ the rpm you'll have with the new gears, assuming you have the same tires, etc.



So, if I have a 6 speed and 3.73's, and cruise at ~ 2,000 rpm at 60 mph currently....and swap in 4.10's, I would RAISE my rpm from 2,000, to ~ 2,180 rpm.

That means at 60 mph in 6th, I'd go from 2,000 rpm to 9% more rpm, or 2,180 rpm.

IE: 4.10's would add ~ 180 rpm at 60 mph in 6th.

For comparison....going from stock 32" tires, to 35" tires, DROPS your rpm.

32/35 = ~ 8.6% change.

So, the FINAL change would mean that, if you swapped on 35's from 32's, and 3.73's for 4.10's, you'd be RAISING the rpm by ~ 9%, and REDUCING the RPM by ~ 8.6%....pretty much a wash as far as final gearing went. (~ 0.4 % total change...)



Of course, some people were not happy with 3.73's and 32's to start with, and, 35's have a little more rolling resistance than 32's...so, some people would prefer to sacrifice some mpg for some ooomph.



That's primarily why the people who DO swap gears go for the highest numerical ratio they can get, and still get the minimal mpg they can live with, for the maximum ooomph.

If you want more mpg...leave the 3.73's and have a deeper overdrive, and 8.6% lower rpms....sort of like if your jeep CAME with the factory 3.21 diff gears...and was MAXIMIZED for MPG.

(3.21/3.73 ALSO = ~ 8.6%)



As a lot of people STARTED with 4.10's....and adding larger tires meant 4.88's were compensating for the tires to get back to stock performance/mpg for THEIR OEM starting gearing, etc.

And - 5.13's, etc...give MORE ooomph, and less fuel efficiency.

Of course, as a group, we tend to be less worried about fuel efficiency, or this would be a Prius forum, etc.

 

I went from 3.73 to 4.10's due to the fact I bought the rubi 44!! I was able to pick up a used set of 4.10's for my rear 44 for $20.00. I have decent power running 33's but if I went up to 35's or 37's I would def. go with 5.13's!!

 

I found this site very helpuf when i needed to regear my TJ. play with the numbers a bit and see where you want to be.

http://www.angelfire.com/fl/procrastination/rear.html

I decided on 4.88 in my Tj since it now 90% trail rig and 10% street use.

hope the link helps you out.
BTW here is the tranny gearing for the 6 speed manual
Gear Ratios 1st 4.46
Gear Ratios 2nd 2.61
Gear Ratios 3rd 1.72
Gear Ratios 4th 1.25
Gear Ratios 5th 1.00
Gear Ratios 6th 0.84
Gear Ratios Reverse 4.06





07 JK Unlimited
3 inch BDS suspension lift
33x11.5x16
JKS Quicker Disconnects
Warrior Products Tube Doors
Mopar Off Road Rear Bumper
Oil Pan Tranny Skid Plate by SkidRow
Custom Front Winch Bumper by RoundStar OffRoad
Skyjacker Adjustable Rear Track Bar
Skyjacker Brake Line Extenders
Rock Krawler Adjustable Front Lower Control Arms
And Plenty of "CHARACTER" From rocks and Trees
“A bad day wheeling is better than good day in Prison!”
^ YCP 4X4 motto ^