re gear question manual trans

[callerys]

Live in South Denver area (Castle Rock), have a 2019 rubi manual trans/v6.

living at 6300 ft at home it drives like a dog (for last 6 years). Finally have the money to do some gears.

Any recommendations on shops close to me? thinking either 5.13 or 4.88. Staying on 33's. Just want more power to at least
use 5th and 6th gear on the highway.

Thanks

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[X35]

At that elevation with the naturally aspirated 3.6 I’d go 5.13. You’d then give yourself a little room if you ever decide to go to 35’s if you find yourself over revving on the 33’s. Take my advice with a grain of salt though as I’ve never dealt with the altitude you have out there. I’m at 670’ above sea level and the 4.56 gears on 35’s with the 8 speed auto is great here in eastern PA. Good luck in your decision

 

[grimmjeeper]

4.88s would be decent with 33s for sure. 5.13s is a bit more than you would probably want unless 35s are in the future.

Oh, and hello from Castle Rock, neighbor.

 

[Apples491]

I drove mine home from Iowa with 4.88s and 33s. Yes it had plenty of passing power in 6th but also terrible gas mileage. 1st gear was all but useless. Like, barely get moving before having to shift. But 2nd wasn't quite short enough to act as 1st.

I'm running those same 4.88s with very heavy 37s now and it's a bit worse than stock. I think 4.88s would be perfect with 35s. I personally think 4.88s are too much on 33s with the manual.

As for shops, The Edge Automotive is in Lakewood and is pretty much the gold standard in the Denver Metro. High Country 4x4 will also do gears on Jeeps. IIRC, @chevymitchell is in Pueblo now and might be convinced to do gears.

 

[callerys]

Any shop recommendations? Out usual Elite Autoworks doesn't do gears.

 

[grimmjeeper]

Any shop recommendations? Out usual Elite Autoworks doesn't do gears.

Call The Edge automotive. The rare times I don't do my own work, I take it up there. They stand behind their work.

 

[chevymitchell]

I drove mine home from Iowa with 4.88s and 33s. Yes it had plenty of passing power in 6th but also terrible gas mileage. 1st gear was all but useless. Like, barely get moving before having to shift. But 2nd wasn't quite short enough to act as 1st.

I'm running those same 4.88s with very heavy 37s now and it's a bit worse than stock. I think 4.88s would be perfect with 35s. I personally think 4.88s are too much on 33s with the manual.

As for shops, The Edge Automotive is in Lakewood and is pretty much the gold standard in the Denver Metro. High Country 4x4 will also do gears on Jeeps. IIRC, @chevymitchell is in Pueblo now and might be convinced to do gears.

Thank you @Apples491.

I am available down here for some gear work. Schedule is pretty flexible.

 

[grimmjeeper]

That @chevymitchell guy does good work too.

 

[Badunit]

If you overgear it you will limit your top speed on the highway. My opinion is to keep the engine at 2500 (or below) for steady long-term cruising to keep the cam on the low-lift rollers and off the high-lift sliders. Go out on the highway in high gear (6th with a manual) and find what MPH that equates to with the stock differential ratio. Consider that to be your top cruising speed right now. After regearing, your new top speed will be the old top cruising speed * old ratio/new ratio.

Someone else already mentioned the other end of the scale, whether it makes 1st gear nearly useless (granny gear) while not making 2nd gear into a good "1st" gear for starting out.

 

[OminousSkitter]

I drove mine home from Iowa with 4.88s and 33s. Yes it had plenty of passing power in 6th but also terrible gas mileage. 1st gear was all but useless. Like, barely get moving before having to shift. But 2nd wasn't quite short enough to act as 1st.

I'm running those same 4.88s with very heavy 37s now and it's a bit worse than stock. I think 4.88s would be perfect with 35s. I personally think 4.88s are too much on 33s with the manual.

I’m at sea level, but this is my experience with 4.88+33s on the 6-speed. I’m going to go up to 35s though.

 

[NWJeepr]

4.56's as a happy medium? Also, would anything larger than a 4.56 fit in a non-Rubi front diff (what is it, M186/ Dana 30?)

 

[chevymitchell]

4.56's as a happy medium? Also, would anything larger than a 4.56 fit in a non-Rubi front diff (what is it, M186/ Dana 30?)

The Gen III D30 can handle all the way to 5.38 without swapping carriers like the JK.

 

[Stetson]

I live in SLC and have some of the same issues (hills and high altitude).

I want to know how it works out with a higher gear. I have the same power train.

 

[Maverick909]

I don’t live at elevation like 6300 but I wouldn’t go more than 4.88 with 33’s. I currently run 4.88 with 37’s here at 1800 elevation. But I do plenty of mountain driving to get to local trails. With my 37’s on the highway I can still run 17-18mpg

 

[callerys]

4.56's as a happy medium? Also, would anything larger than a 4.56 fit in a non-Rubi front diff (what is it, M186/ Dana 30?)

Its a rubicon

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