Gearing

[clayfuntoo]

I bought 2025 jeep gladiator rubicon x original 33” tires I added 2.5 inch lift and 35 inch tires. You all heard it before no more 8 th gear and gutless in deep snow. I was thinking 4:88 gearing. My future plan for the vehicle is pulling a 3000 lb trailer to off-road locations a commute from there on backroad trails. I do use this vehicle as my daily driver also. What are my fellow experienced jeep peeps thinking about gear choices or is mine about right?

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[Wheelin98TJ]

I think you're right on.

4.88 is a popular choice for 35s and you can still use it with 37s if you decide to go up with your next set of tires.

 

[D_JT]

4.88 is to steep. 4.56 is what you want. 4.56 is also what the Wrangler Xtreme Recon comes with and it has 35". Which makes sense. 4.10 for 33''s. So 4.56 for 35"s. 4.88 is to much. I run 4.88 in my 5 speed TJ with 35"s. But have you adjusted/calibrated the computer for 35"s? My wifes JL Rubicon has 35"s and stock gears and it sees 8th all the time.

 

[Zachanadandy]

4.88 is to steep. 4.56 is what you want. 4.56 is also what the Wrangler Xtreme Recon comes with and it has 35". Which makes sense. 4.10 for 33''s. So 4.56 for 35"s. 4.88 is to much. I run 4.88 in my 5 speed TJ with 35"s. But have you adjusted/calibrated the computer for 35"s? My wifes JL Rubicon has 35"s and stock gears and it sees 8th all the time.

Agree whole heartedly... but wouldn't spend the money to regear by 1 ratio anyway. I see 8th regularly with the stock 4.10s and 37s. You have to drive SLOW and always uphill to never see 8th with 35s. Gutless in deep snow? Downshift. This v6 doesn't make peak torque until 4k rpms and peak hp until 6k+. It's not a gearing issue it's a gear selection one. Axle gears don't do anything outside of 1st gear that a simple downshift won't.

 

[Wheelin98TJ]

4.88 is to steep. 4.56 is what you want. 4.56 is also what the Wrangler Xtreme Recon comes with and it has 35". Which makes sense. 4.10 for 33''s. So 4.56 for 35"s. 4.88 is to much. I run 4.88 in my 5 speed TJ with 35"s. But have you adjusted/calibrated the computer for 35"s? My wifes JL Rubicon has 35"s and stock gears and it sees 8th all the time.

4.88 is probably the most popular choice for those who regear for 35s. And you very rarely (if ever) hear someone say they think it's too deep.

 

[Zachanadandy]

4.88 is probably the most popular choice for those who regear for 35s. And you very rarely (if ever) hear someone say they think it's too deep.

The stock 4.56s and 35s on the xr package were too deep at freeway speeds of 80+ in my opinon. Of all the gearing combos I've run with the 8 speed I found 4.56s and 37s to be the best. Very similar in driving dynamics to the stock 4.10s and 33s. The worst was the 5.38s and 38s. I find under geared much more tolerable than over geared with this transmission.

 

[Wheelin98TJ]

The stock 4.56s and 35s on the xr package were too deep at freeway speeds of 80+ in my opinon. Of all the gearing combos I've run with the 8 speed I found 4.56s and 37s to be the best. Very similar in driving dynamics to the stock 4.10s and 33s. The worst was the 5.38s and 38s. I find under geared much more tolerable than over geared with this transmission.

Your freeway driving speeds of 80+ is also a big factor in tolerating tall axle gears.

 

[Zachanadandy]

Your freeway driving speeds of 80+ is also a big factor in tolerating tall axle gears.

Absolutely... and the speed limit on the way to Moab starts with an 8 so my Jeeps need to be comfortable running those speeds for hours at a time. Of course the 4.7-1 1st gear is the equivalent of a tj or early jk running 6.73 axle gears with the 4.10s so I'd argue it's more than tolerable to anyone who understands how to downshift.

 

[Wheelin98TJ]

Absolutely... and the speed limit on the way to Moab starts with an 8 so my Jeeps need to be comfortable running those speeds for hours at a time. Of course the 4.7-1 1st gear is the equivalent of a tj or early jk running 6.73 axle gears with the 4.10s so I'd argue it's more than tolerable to anyone who understands how to downshift.

Who doesn't understand how to downshift when 98% of us have automatics?

 

[Okie Gladiator]

FWIW I’ve been pleased with 4.88’s and 37’s with my 3.5 inch metalcloak lift. I pull a travel trailer that weighs about 3,000 lbs. Pulling it 65 to 75 mph I’m sitting at 2,000 rpm and holding 8th gear. When not pulling anything it performs as I would expect. Plenty of power and runs through the gears smooth.

 

[Zachanadandy]

Who doesn't understand how to downshift when 98% of us have automatics?

There's only a million threads of people trying to keep it under 4k rpms by manually shifting... and then they complain about the lack of power. The 285hp is adequate... but you're about half that below 4k rpms. Spin the 3.6L and it will pull decently.

 

[Wheelin98TJ]

There's only a million threads of people trying to keep it under 4k rpms by manually shifting... and then they complain about the lack of power. The 285hp is adequate... but you're about half that below 4k rpms. Spin the 3.6L and it will pull decently.

That's a new one to me.

People are stupid is the only thing that comes to mind.

 

[GeekJT]

I bought 2025 jeep gladiator rubicon x original 33” tires I added 2.5 inch lift and 35 inch tires. You all heard it before no more 8 th gear and gutless in deep snow. I was thinking 4:88 gearing. My future plan for the vehicle is pulling a 3000 lb trailer to off-road locations a commute from there on backroad trails. I do use this vehicle as my daily driver also. What are my fellow experienced jeep peeps thinking about gear choices or is mine about right?

A simple forumla to see how far away or close to stock ratio is

New ratio = 4.10 × (New tire ÷ 33)

Or
35s: 4.10 × (35/33) = 4.35 (go 4.56 sweet spot)
37s: 4.10 × (37/33) = 4.60 (almost exact match, go 4.88 for a little advantage)
38s: 4.10 × (38/33) = 4.72 (go 4.88)
40s: 4.10 × (40/33) = 4.97 (go 5.13)

The most common gear ratios to change to is 4.56, 4.88 and 5.13, and yeah there is a 5.38, but the pinion gets pretty small then.

On 35's 4.56 is a little over ratio, and would give you a little better RPM band and mechanical advantage when putting a load on it. (deep snow) etc. Will pick up a little city MPG, will lose a little highway MPG.

On 37's 4.56 is just a hair under an exact match to stock ratio but 4.88 would feel a lot better on 37's given their weight, having the mechanical advantage would help it quite a bit, gladiator being underpowered.

38-40s 5.13 hands down for sure.

 

[Sikjeep2]

I would 100% would not do 4:88 with 35s.

I would say 4:10 or 4:56

 

[T-Rock]

I've had two respected shops tell me that you have to consider weight as well. The 4.56 gears Jeep uses on the X packages are for the stock vehicle at that weight. If you have a JT & add things like a shell, rack, RTT, decked system, etc the overall weight impacts the behavior of the gearing. Multiple locals that have gone 4.88 on 35's are raving how they love their JT again, but they have RTT's with racks or shells and sometimes tow.

My personal experience is that since I put 35's on my Mojave with 4.10 gears I rarely see 8th gear, get an average of 15 mpg on the highway and 13-14 around town or mountain roads, 8-9mpg if I tow. I feel I need a change. A friend's father put 4.88 on his JT at the beginning of the year, has a shell & extra weight on his rig and has been averaging 21 mpg on the highway and 18 on trails.

So... I am not arguing against 4.56 or anything, only sharing what I have heard.
I am certainly strongly considering 4.88's in my future...but will follow to hear of other's experience and knowledge on this topic. I have a month or so before I pull the trigger.

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