I am in the process of re-building my yj and need some opinions as to what atlas gearing I should go with. I mainly wheel the east coast which can be wet and muddy at times, and dry and rocky at others.

The specs for the Jeep will be

stock 4.0, NP435, 60 front and 14 bolt rear with 5.38 gears. and i am in the process of looking for a set of used 39 krawler's.

Now what geared atlas should I buy?

4.3 atlas---crawl ratio 154 to 1 (1st gear) 77 to 1 (2nd gear)

3.8 atlas---crawl ratio 136 to 1 (1st gear) 68 to 1 (2nd gear)

5.4 atlas (4 speed)---low low crawl ratio 194 to 1 (1st gear) 97 to 1 (2nd gear)
---high low crawl ratio 97 to 1 (1st gear) 48 to 1 (2nd gear)
---low high crawl ratio 71 to 1 (1st gear) 35 to 1 (2nd gear)

10.3 atlas (4 speed)---low low crawl ratio 370 to 1 (1st gear) 185 to 1 (2nd gear)
---high low crawl ratio 136 to 1 (1st gear) 68 to 1 (2nd gear)
---low high crawl ratio 97 to 1 (1st gear) 48 to 1 (2nd gear)


I realize that the 10.3 4 speed atlas is stupid low and not really realistic for my rig, but in your opinion, is the 5.4 atlas 4 speed and its extra gears worth the extra money? and if it is not worth the extra money which 2 speed should I buy.

Please keep in mind that the lenght of the 4 speed is not an issue since I am going to run a Novak adapters kit on the tranny to achieve a short length tranny and the Jeep is sitting on xj springs in the rear.

Please do not reply with buy a stak t-case. I would like opinions on the atlas only please.

Thanks
Brandon

5.4 4 speed for sure. I want one myself but the funds are short right now.

5.4 = Great Crawling
2.7 = Great Wheel Speed

5.4 4 speed for sure. I want one myself but the funds are short right now.

5.4 = Great Crawling
2.7 = Great Wheel Speed

X2

i have the 3.0 atlas in my rig with rockwells and 44's and its damn near perfect for every where i have been on the east coast,, i can generate wheel speed, but i can still crawl fairly decent.. i just put my case up for sale in the classified section, b/c i am steeping up to a set of 49's on 20" wheels and i want a little better gearing over the larger and heavier tire.i am only going to an atlas 3.8 though. i have a customer who has a 4.3 atlas and the last 2 times we have gone to tellico(once dry and once with it raining the whole time we was there) he had to run his jeep in high range simply b/c he couldnt generate enough wheelspeed to get up and over the obstacles.. he was running a healthy small block and 37" crawlers with 4.88 gears. but since you have a manual i would go with the 4sp, or the 4.3 b/c you can start out in any gear you want unlike us guys with autos(unless we have manual valve bodies)

I agree with you guys...

I guess then my choice is 4.3 atlas which is cheaper

or 5.4 atlas 4 speed with more options

with a stick 4.3 definately...between 2 gears in the case and a 4 speed it seems like you could get the wheels spinning like you need them to

I'm fixing to go to an auto and Iv'e been going crazy trying to figure out which one I want...not trying to change your mind or anything but why are you dead set against the stak?

you might think 10.3 is stupid low, but I love mine!! I kept 4.10:1 axles, and with that 10.3:1 fawking low, I can juuuust bearly drive through the brakes.

BEST MOD I'VE MADE!!

with a stick 4.3 definately...between 2 gears in the case and a 4 speed it seems like you could get the wheels spinning like you need them to

I'm fixing to go to an auto and Iv'e been going crazy trying to figure out which one I want...not trying to change your mind or anything but why are you dead set against the stak?


I'm putting a TH350 behind a 350SBC in my new project so I'm going with
the 10.34:1 4sp Atlas so I get some low range. The TH350 1st gear's only
2.52:1 and with 5.13's in the axles I'll net a 134:1 crawl ratio. The part I
really like is that I can leave the planetary in 1:1 and just use the 2.72:1.
Gives lots of options on gearing.

More gearing options with the 4speed 5.4 Atlas-how can you lose??:D

How bout a flipped and doubled 231