Picking an Atlas

[Woodrow]

I'm close to ordering an Atlas 2sp (5.0:1) for my 97 TJ with a stroker (25% torque bump over stock) and an ax-15.

Its a daily driver on 33s w/ 4.11 gears and e-lockers.
Front Dana 30 with 27 spline 4340 and rear Super 35.

What I'm trying to do:
1) better crawl ratio (now = 42.8, with 5.0:1 Atlas = 78.7)
2) less clutch use/more finesse on trail

Other advantages:
1) front digs
2) 2Low option
3) almost 2" longer rear driveshaft

Disadvantages:
1) time and money
2) not a 4spd Atlas (but that would shorten the rear drive shaft by about 3" and might be too much torque for my axles-actually the 2spd might be as well...)
3) might force the body lift I've been avoiding and/or T-case skid and trans mount mods.

What am I missing?
Other thoughts from those who have been down this road?

 

[Wildman]

@Alex01 can you comment?

 

[Alex01]

@Alex01 can you comment?

The jeep became a whole new rig after dumping the 231.

5:1 was by far the most gamechanging mod I've done followed by the hydro assist (I may consider that more of a quality of life mod though) To shortly sum it up you'll get a new ultra low first gear followed by your 231 ratio in 2nd and lose your current 5th.

Downside is I can only go 15mph in low but I should be in 4 high or likely 2 high if I'm going close to that speed anyways.

 

[Duck Doctor]

I have an Atlas 4.3:1 in my YJ and have no complaints. I’m a fan of the 2 low feature and can’t say enough about the ultra low first gear. Rarely use the clutch off-roading. Last time I ran the rubicon trail I stalled once.

Good move going 5:1 instead of 4.3:1. Wish I had that extra low gearing.

 

[SkylinesSuck]

Sub'd for input. The only thing stopping me from a 2 speed Atlas is trying to make it fit with my Savvy TT. That's a hill I plan to climb one day anyways.

 

[macleanflood]

There's a D300 for sale north of me for $800. Man I should snag it. My 97s set up just like yours.

-Mac

 

[Jerry Bransford]

Consider also converting your AX-15 to the 32RH automatic (an easy conversion) for a big bump up in the effective crawl ratio, 2-3X more low-end torque for getting up and over difficult obstacles, and an infinitely low 1st gear ratio. All courtesy of the 32RH's torque converter. Converting my AX-15 to the 32RH was right there for me with f/r lockers in terms of dramatic offroad improvement on very difficult trails.

Not to mention you won't need as low of a ratio for the Atlas if you convert to the 32RH.

 

[Akitadog]

I love the 5.0:1 ratio from the 2.72 in the 231. The only drag was waiting 6 moths for delivery.

 

[Woodrow]

Consider also converting your AX-15 to the 32RH automatic (an easy conversion) for a big bump up in the effective crawl ratio, 2-3X more low-end torque for getting up and over difficult obstacles, and an infinitely low 1st gear ratio. All courtesy of the 32RH's torque converter. Converting my AX-15 to the 32RH was right there for me with f/r lockers in terms of dramatic offroad improvement on very difficult trails.

Not to mention you won't need as low of a ratio for the Atlas if you convert to the 32RH.

Ha! I knew that was coming. I’m a new comer to rocks but a convert. After spending some back-to-back time in my manual TJ and an 8 spd auto JLUR in Moab this year, I know you are right. However, mine is a daily and I like a manual so much better on road (and off road when not in super technical stuff) that I’m willing to suffer more before I cave to your obviously correct logic

 

[Woodrow]

I love the 5.0:1 ratio from the 2.72 in the 231. The only drag was waiting 6 moths for delivery.

2 mos, now

 

[Woodrow]

The jeep became a whole new rig after dumping the 231.

5:1 was by far the most gamechanging mod I've done followed by the hydro assist (I may consider that more of a quality of life mod though) To shortly sum it up you'll get a new ultra low first gear followed by your 231 ratio in 2nd and lose your current 5th.

Downside is I can only go 15mph in low but I should be in 4 high or likely 2 high if I'm going close to that speed anyways.

You are convincing me, not that I needed much. Do you have the trail series with the longer tail housing that holds the stock speedo gear?
edit: also, did you go bigger on your u-joints or stay with 1310?

 

[NskLJ]

You won’t be able to flat tow it with the Atlas.

 

[Apparition]

You won’t be able to flat tow it with the Atlas.

He’s got a trailer. But, you can flat tow if you pull the driveshaft so it can be done if really needed.

Mike, the gearing would be a game changer for you.

 

[Wildman]

He’s got a trailer. But, you can flat tow if you pull the driveshaft so it can be done if really needed.

Mike, the gearing would be a game changer for you.

I thought the Atlas could be flat towed if you stopped every XXX miles and ran the engine? Maybe misunderstood or read something wrong. But it wouldn't surprise me since you can't with the STaK's either.


Edit: Since 2018 they now offer a tailhousing that allows you to flat tow the Atlas.

Flat Tow Tailhousing

Introduced in 2018 the flat tow option was released for the Atlas transfer case. This new option uses a new rear output shaft that is connected to a gerotor pump assyembly. The Atlas pan has a pick up screen that pulls oil from the main case pulling it into the tailhousing and down the output shaft lubricating the bearings while driving and being flat towed. The length of the tailhousing is the same as the standard Atlas. It does not have the mechanical speedometer gear but offers an electronic pick up for a Jeep , GM, or STD which has no pick up.

P/N AFT-JP Flat Tow tailhousing with Jeep sensor

P/N AFT-GM Flat Tow tailhousing with GM sensor

P/N AFT-STD Flat Tow tailhousing witout a speed sensor

 

[PNW_LJ]

I thought the Atlas could be flat towed if you stopped every XXX miles and ran the engine?

Just like a Samurai

 

[JMT]

I'm close to ordering an Atlas 2sp (5.0:1) for my 97 TJ with a stroker (25% torque bump over stock) and an ax-15.

Its a daily driver on 33s w/ 4.11 gears and e-lockers.
Front Dana 30 with 27 spline 4340 and rear Super 35.

What I'm trying to do:
1) better crawl ratio (now = 42.8, with 5.0:1 Atlas = 78.7)
2) less clutch use/more finesse on trail

Other advantages:
1) front digs
2) 2Low option
3) almost 2" longer rear driveshaft

Disadvantages:
1) time and money
2) not a 4spd Atlas (but that would shorten the rear drive shaft by about 3" and might be too much torque for my axles-actually the 2spd might be as well...)
3) might force the body lift I've been avoiding and/or T-case skid and trans mount mods.

What am I missing?
Other thoughts from those who have been down this road?

What rear axle do you have? I’m assuming a Dana 35 since it’s a 97’.

You’re only missing one thing: a body lift is the best bang for your buck mod. Then just raise the 6 central mounts and do a rear frame tuck. It will practically look like you don’t have one. Then throw on the 35’s and make your adjustments.

As far as the Atlas, a 78:1 will be a huge help. I’m at 81:1 and came from the lurching experience of about 56:1. In snow I wish I had the 2.72:1, but I get away with shifting into 4H. NSG370.

 

[Woodrow]

He’s got a trailer. But, you can flat tow if you pull the driveshaft so it can be done if really needed.

Mike, the gearing would be a game changer for you.

Too soon for the Moab 2024 thread?

 

[Woodrow]

What rear axle do you have? I’m assuming a Dana 35 since it’s a 97’.

super 35, 4.11

You’re only missing one thing: a body lift is the best bang for your buck mod. Then just raise the 6 central mounts and do a rear frame tuck. It will practically look like you don’t have one. Then throw on the 35’s and make your adjustments.

I actually have had a Savvy 1.25” body lift on the shelf for a couple of years. I’d like to get the Atlas in without it but that seems unlikely. If I do the body lift, I can clear 35s with my current suspension. If I do that, I’d probably re gear from my current 4.11 (which is actually good on road with 33s and the 25% stroker power bump) to the recommended 4.88.

As far as the Atlas, a 78:1 will be a huge help. I’m at 81:1 and came from the lurching experience of about 56:1. In snow I wish I had the 2.72:1, but I get away with shifting into 4H. NSG370.

yep. I feel an AA order coming this week.

 

[Jamison C]

That's a hill I plan to climb one day anyways.

You’d climb more if you got an atlas

 

[Apparition]

Too soon for the Moab 2024 thread?

Pritchett 2024