• Welcome to the new NAXJA Forum! If your password does not work, please use "Forgot your password?" link on the log-in page. Please feel free to reach out to [email protected] if we can provide any assistance.

Atlas 2: 3.0:1 or 3.8:1

J

jake3240

NAXJA Forum User
Location
Norfolk, VA
I can't decide between the 3.0:1 or 3.8:1 Atlas transfer cases. I'm running a 4.0, ax-15, 231w/sye, dynatrac d44/60 front, and Ford 8.8 rear with 4.88's on 35's. Most people say go with the 3.8 or 4.3, but I'm wondering if that's just too low for me. Most of the wheeling I do is dirt trails with rocks thrown in and steep loose hill climbs(Dig Dogs offroad). I enjoy getting on the gas and going fast more than I do super slow, technical crawling. I'll probably be going with 37's before long, too. Here's my question: Is the low crawl ratio of the 3.8 more of a benefit when I do get in the rocks than the loss of the 5th gear 4low top speed when you're gunning down a trail? For those with the 3.8, do you ever feel like it's too low? Anyone running a 3.0?

BTW, the reason I want to go with an Atlas is because I keep breaking the 1310 driveshafts and feel like I need something stronger, and with the 26 spline front output on the 231, there aren't any options I see. I've broken the front shaft twice at the CV yoke and the slip splines are starting to twist on my rear shaft(both of these are Tom Wood's)

Thanks in advance for any input.
 
"Most of the wheeling I do is dirt trails with rocks thrown in and steep loose hill climbs"

how do you keep breaking driveshafts on only dirt roads?

Go at least 4:1 in a manual if not 5:1 .

If it was an auto I would say 3.8 or 3.0 .
 
why are you in 4L gunning down a trail? Thats probably why youre breaking shafts, if youre gunning it down a trail it seems like 4H would be the better choice.
 
Big Dogs has a little of everything. There are rocks there, but there's also a lot of loose climbs that need momentum and wheel speed starting out to get up, not to mention mud when it gets wet. I'm afraid a 4.3 or a 5:1 might be too deep and high range might be too high. I'm sure the broken driveshafts are due to my love for the skinny pedal. I'm looking for something that will hold up to the abuse I give it.
 
Big Dogs has a little of everything. There are rocks there, but there's also a lot of loose climbs that need momentum and wheel speed starting out to get up, not to mention mud when it gets wet. I'm afraid a 4.3 or a 5:1 might be too deep and high range might be too high. I'm sure the broken driveshafts are due to my love for the skinny pedal. I'm looking for something that will hold up to the abuse I give it.
 
If you are doing any technical rockcrawling. You will not be low enough. Obviously you can finess it but its a decision between clutch slipping in the rocks and lurching forward or controlled crawling.

This is usually where 3speed cases or doublers come into play. 5:1 should put you right in the ballpark for crawling. 3.8:1 will work if you if your ok with having less speed control when crawling.

With an ax-15 your crawl ratio should be around 100:1.
 
Get the deepest case you can. Even if you're over geared and need more wheel speed for something, you've got a manual, just upshift another gear. My mid range is 3:1 and its great for trail riding, but I have 5.38's and an auto. Anything very technical I'll drop down to 5.44:1 and crawl
 
Your driveshaft issue is that your running tom woods.

4.0/AX15/4.3 Atlas/5.38's did one year on 38's the past 2 on 42's. I find it to be perfect. Only once did I want to be lower geared. I'm running a stock shortened frt driveshaft in frt and a retubed frt driveshaft in the rear haven't broken yet
 
Thanks for the input everybody. I guess the 3.0 is out. I'm leaning more towards the 3.8 or 4.3 now. I don't really see myself being able to use or enjoy a 5:1. I don't plan on going bigger than 37's, but I want to be able to beat on them pretty hard without breaking things. I also want to keep it streetable still. If I want to go bigger than 37's I'll build a buggy and get a tow rig. I'm done with Tom Wood's shafts too.
 
No questions asked, I would do the 5:1, with having an AX-15..


I'm going 5.38s on 37-40" tires, and Im ordering the 11.70:1 Atlas 4 speed. That's with a v8/Auto..

You cant be "over geared" Just shift..
 
We have a 3.8 with 35's and 5.38's, and can do 40 mph in low range when we need to get on it.

I'm actually looking at going to a 3.0 (we race..) but I would suggest a 3.8 for you. If you lived with bigger rocks, I'd say a 4.3 for sure, but you east coast guys just don't seem to have the kind of rocks we are used to out in the dry half of the country.
 
NW-ZJ-SCOTT said:
No questions asked, I would do the 5:1, with having an AX-15..


I'm going 5.38s on 37-40" tires, and Im ordering the 11.70:1 Atlas 4 speed. That's with a v8/Auto..

You cant be "over geared" Just shift..
Click to expand...
I disagree there's a point where your gonna loose power through all the gearing, and east coast things are wet and times you need the wheel speed
 
Just buy a 4 speed and everyone will be happy!
 
'loose power through gearing' makes no sense at all.

you might run out of RPM's, but thats a whole different situation.
 
cal said:
'loose power through gearing' makes no sense at all.

you might run out of RPM's, but thats a whole different situation.
Click to expand...

Think of it how you loose HP on a wheel dyno vs a engine dyno
 
If you were adding more drivetrain parts, like another case, i could see a power loss. Really the only thing youre losing is wheel speed. Id say the power(torque) even goes up since it becomes easier and easier to brake parts farther down the drivetrain as you go lower and lower with gearing because of the torque multiplication
 
ROBZ95Xj said:
Think of it how you loose HP on a wheel dyno vs a engine dyno
Click to expand...

LOSE. IT'S LOSE. NOT LOOSE.

Your lugnuts are loose. You lose brain cells when you fall on your head.
 
You must log in or register to reply here.

Similar threads

T
1 Ton steering clearance issues
Replies
9
Views
847
XJChang
X
A
dana 30 low pinion 488 on 33.6 inch tires ?
Replies
6
Views
1K
75SV1
7
A
2000 xj aw4 on 34s 4.88 or 5.13
2 3
Replies
49
Views
5K
Andre2000
A
W
Newbie with an XJ
Replies
8
Views
176
RCP Phx
R
T
Brake bleeding: vacuum/pressure or old school?
Replies
10
Views
707
lawsoncl
L
Back
Top