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Doubles, crawl boxs, and atlas

F

farvaszx6r

NAXJA Forum User
Location
sac ca
So I'm looking into upgrading the t-cace in my xj and im really liking the thought of a three or four speed transfer case but im kinda on the fence about which way to go

I want a low ratio of around 5:1. I see only 3 real options and would like some opinions and experience with them

1st is the atlas 4 spd its simple Bulletproof very expensive

2nd is the 205/231 doubler not as expensive as the atlas but it's very heavy

3rd is the 242amg with a crawl box the amg is a beefy t-cace with a large chain a lockable center diff and external Cooling but would give me 7.34:1 low gear and i think that might be to much with an automatic.

All 3 options allow for front and rear dig but the 242 also has a full time 4x4 option which is awesome in the snow

Let me know what you guys think
 
i would replace the 205/231 option with a 231/300. you remove the chain driven 231, and get selectable front and rear outputs.

i had a 231 crawl box and dana 300 at one point... got them for pretty good deals too. i was looking at upgrading the front and rear outputs, possibly 4:1 in the 300, and a 6 gear planetary in the crawl box. by the time i was done adding it up, i wasnt that far off from a 4 speed atlas... i sold it all and will be going atlas in the future.
 
There is also the NWF Eco Box. Put it in front of a 231 with a 6 pinion planetary and wide chain conversion and you should have a fairly stout an inexpensive setup. I would recommend adding a rear support to the T-case however to help deal with the additional loads.

http://www.northwestfab.com/NWF-Eco-Box-Billet-Planetary-Doubler-Case_p_2403.html

This is the route I'll more than likely go at some point.
 
I got the Atlas 4 speed. It has been installed and in DD use since June 2008 and I could not be happier. Worth every penny, to me. However, I have a manual trans. The low-low ratios may not be AS heavenly with an auto as they are for me. I have the 10.34 box.

That one gives you 2.72 ratio and 3.8 ratio, which is a great trail gearing. I use the 10.34 frequently on technical climbs. Although in an automatic, I imagine it would be less used. If you did get that one, make sure your brakes are great, as it would idle through almost anything. :thumbup:

My instinct says I would not have gone as low with an auto, although I have heard a couple of auto guys chime in over the years that they like the 10.34 as well.
 
The np 205 is a gear driven t-case that came in 1-ton trucks and has both driver and pass drops what makes the dana300 more suitable
 
weight definitely being a downfall of the 205. i dont know what finished length comes out to compared to the 300. something to think about if you arent stretching the rear.

the 205 is rock solid though. a couple people we talked to at the hammers last year were running stock 205s because they were breaking atlas cases. (their words)
 
From my research the 300 required some upgrades to strengthen it and by the time most were done they said they should have bought an atlas so i really didn't consider that.

The 231/205 combo with sye works out to be the same length as a 231 with a slip yoke and the 205 only needs a twin stick kit but the fact that its cast iron is not something im thrilled about.
 
Staz sells an adapter and input shaft to take the dodge np203 range box and put it in front of the dana 300. It is another option if you can get both cases easily. However you begin to approach the cost of an atlas at the price of all of the adapters and shafts you need to run it.


Sent from my iPhone using Tapatalk
 
I was going to go 4spd Atlas but.went with a 5.0 csse I found no need for the 4 speed as 1st gear works well for crawling and OD for wheel speed . If you are looking at going fast with a 4.0 I can see the 4spd case with a 2.0 option ,but otherwise it is pointless having a 4spd case with a deep low of only'4.3-5.0 on a crawler type trail rig .
 
97xjsam said:
Just for kicks n giggles I just looked up an Atlas 4 speed... $3,000
Click to expand...

Pirate has the best shipped to the door prices on new cases built to your spec .$2350 for a 2spd ready to bolt in . Once you put all the good stuff in a d300 it will be close and not be as strong ...lol...but yeah the Atlas is not a cheap part . I think for tires 37 and under the stock 231 with sye and right gears in the pumpkin are the best deal . The 231 holds up even to 40+ you just need to watch the chain and keep it skid plated the lack of those two things are what kills most of them I never killed my 231 on 40 boggers . I only upgraded to the Atlas because I went to 44 tires and needed a bit more gear and was not going to waste cash on a Tera low or a retard priced JK 241 .
 
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