First Impressions 3.45 to 4.56 Gears

[Ran4]

Randy,

I'm not totally to the point of giving up on the 3.45s, but your really high recommendation and enthusiasm of the 4.56s are certainly noted, and will most certainly use this to help sway my decision in the future.

For 35s this is so borderline subjective. Especially on a good 2.5" inch lift and disconnected sway bars. For any larger tire a re-gear is most certainly necessary, (beyond any shadow of doubt). 4.88s or even above 5.xx will be required for the truly bigger rubber. However (for me), 35s are as large as I'm willing to go on my Sport.

I too do a lot of off-roading. Maybe not as aggressive as you but difficult to severe is certainly in my comfort zone. I'll gladly let the professionals tackle the extreme boulder bouncing crap.

Living along the Colorado Front Range my desire is to see way more of my state and truly experience the Rocky Mountain wilderness. Not necessarily scrape my way through the most rockiest ravines in doing so. However, the more than occasional (more than difficult) obstacle must be expected anywhere within our National Forest System trails.

So your setup indeed has a lot of appeal. Thanks for sharing your experience, reasoning and thoughts on the matter.

Thank you so much for your advice and feedback. Very much appreciated.

Jay

You're welcome, Jay.

We already have plans for CO and UT again this summer. I 'might' (though I don't really need to) swap out my spacer lift for a new 2.5" coil spring lift. We'll see. I like how the Jeep rides now (I failed to mention above that I also have Rubicon springs and shocks to go with the spacers).

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[cainblue49]

Hey guys I rarely post but I have been running BF Goody's AT 315's on a 17" rim with Mopar lift for 60k miles, I am about to re-gear form stock to 4.56 and am stoked. I have always managed averaging about 20-21mpg and 8th is only for either flat land with when drafting, a slight tailwind or down hills. I am ok with putting my foot in it to go but doing the re-gear for two primary reasons both of which deal with wear and tear. Gear hunting over 55mph and engine rpm in doing so. It is not major but less downshifting to maintain hwy speeds annoys me. I know I will be running a little higher Ron but growing up on farms, maintaining a consistent rpm with minimal fluctuations is best on oil and engine life plus I really think hwy mpg with see an increase and definitely city mpg will increase. I will update once it gets done. Will be continuing with a 35" tire but switching to a hybrid tire and an air locker in the rear. 3.45 has not and is not terrible by any means but my round trip is 60miles+/day most of the time just under 60mph but hoping to run 65+ and get the same or better mpg.

 

[omnitonic]

When this thread popped back up, I realized why I expected to get some fuel economy back when I regeared. I didn't. I put the 35s on (315/70R17) and dropped from 21 to about 15. Now that I'm on 4.56 gears, there she sits. I wanted to see 19, and would have settled for 17. Nope. It's still 15.

Oh well. It does drive a whole lot better on the 4.56 gears, both on-road and off. It drives nicely. It just gets crappy gas mileage. Sigh.

 

[omnitonic]

When this thread popped back up, I realized why I expected to get some fuel economy back when I regeared. I didn't. I put the 35s on (315/70R17) and dropped from 21 to about 15. Now that I'm on 4.56 gears, there she sits. I wanted to see 19, and would have settled for 17. Nope. It's still 15.

Update at the end of 2023: I took off my Mickey Thompson Baja MTZ P3s and put on a set of Falken Wildpeaks, and I'm up to 18+ mpg. Less road noise, and better wet traction too. It's not like I go mud bogging in a $60,000 vehicle that still has many years of payments in its future, so this seems better. Now I just need to find some dumb kid with a K&N cold air intake and a hot but in my opinion stupid girlfriend to buy the old tires off me. Come on, Dakota Dan, Prince of the Hydro-Lock, come buy my old shoes! Your girlfriend will continue to stroke your arm and tell you what a man you are while I rescue your dumb ass who couldn't take care of a woman.

 

[DrummerDudeNJ]

Was doing some research on new gears yesterday and stumbled upon this thread. Thanks @Ran4 for the great write up. I just ordered the Yukon 4.56 front and rear kit, should be here in a few days.

Currently running 295/70/18 MT ATs on Fuel rims... they BE HEAVY! The stock 3.45 gears DO turn them ok, but without my SprintBooster turned on things feel a lil sluggish. I'll sometimes see 8th gear on the highway but at 75-80mph she lives in 7th. Getting about 17mpg now, so I'm confident that I should get some mpg's back along with much improved torque and performance.

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