Topic: Atlas Dilemma

[Jeffy]

So, I've been thinking about getting an Atlas for a while now.  Was close to pulling the trigger then some money issues came up.

With the Jeep turning into more of an Expedition vehicle with some crawling, I'm wondering if I should get a 5.0:1.  Their top seller seems to be the 4.3:1 still.  Then there's the 3.8:1.  Would the 4.3 or 3.8 be a better choice.  I'm thinking the only time I'll really need low is when crawling over rocks.  Otherwise, I'll be in 4WD HI.  I don't really have any plans to do anything much harder then the Rubicon, Fordyce or maybe Dusy.  Otherwise it will probably be fire trails.  Think 5.0:1 would be too low?  Or should I just bite the bullet and get the Atlas 4.0 with 11.70...

[aw12345]

Plug your trans and transfercase numbers in this calculator and see what gives you the nicest gear spread. For me the 5:1 is nice since it gives me essentially a 12 speed trans. I eould go with the transfercase that does not give ratio overlap.
I really like the gearing so each gear is a small step up, unless you would like to have gears between gears

http://www.grimmjeeper.com/gears.html

[sharpxmen]

i would do an NV3550+241OR, probably the same money in the end and you were thinking of swapping the transmission at some point if i recall correctly. If you go with the Atlas i'd say 4 speed if you can hold off until funds are available, but of course 5 or 4.3 are also good choices.

[Jeffy]

i would do an NV3550+241OR, probably the same money in the end and you were thinking of swapping the transmission at some point if i recall correctly. If you go with the Atlas i'd say 4 speed if you can hold off until funds are available, but of course 5 or 4.3 are also good choices.

Cost would be as much if not more then for a Atlas 4.0 and would only give me 60:1 final.  The AX-5 has been fine for me.  If I keep the engine, I'll probably keep the transmission.  For the street, it does well.

[sharpxmen]

i think it's 70 to 1 (3.93x4x4.56) but yeah, not a super-low crawl rate.

[neale_rs]

To keep it truly multi-purpose some doubler is the way to go.  The 2.71 is very good for general use in dirt and wet trails, the 4.3:1 is what you will use most of the time in rocks but is too low for general trail riding (it is a pain to have to shift to high range for easy sections) and not low enough for some very technical sections, so having something at or below 5:1 is also good.  Atlas 4 speed is my recommendation due to the overall length but any doubler will do like two NP231s,  or an NP231 with a Dana 300 with 4:1 gears, or a Klune V with the NP231, but these would be more complicated installations (might want to move the engine forward).

[FourbangerYJ]

You know what I am gonna say...
But I will say it anyway.  4 speed Atlas. You have it all in one package. 2.7:1 for fire roads, 4.3:1 for rough stuff, 11:1 for the real crazy stuff or things you want to take your time on.
20 forward speeds and 4 reverse speeds = happy,happy,happy

[aw12345]

For what he wants to do with it a 6 speed trans with a 4:1 or 5:1 Atlas will make him a very happy camper. The extra 1000 bucks is much better spend on a transmission that will give him usable gears on the street and in high range. a 4 or 5:1 2 speed Atlas will give him all the crawl speed he would ever need, yet allow him to run atleast 15 mph in top gear in low range when you wind the lil squirel box up.
There is nothing on any of the trails he wants to run that would require 150:1 crawl ratio. Something in the 90 - 100:1 ratio will do just fine and still be able to get enough wheel speed to bump ledges in second or 3 th gear.
The 6 speed gives a nice gear spread to scream up sand hills also

[Jeffy]

For what he wants to do with it a 6 speed trans with a 4:1 or 5:1 Atlas will make him a very happy camper. The extra 1000 bucks is much better spend on a transmission that will give him usable gears on the street and in high range. a 4 or 5:1 2 speed Atlas will give him all the crawl speed he would ever need, yet allow him to run atleast 15 mph in top gear in low range when you wind the lil squirel box up.
There is nothing on any of the trails he wants to run that would require 150:1 crawl ratio. Something in the 90 - 100:1 ratio will do just fine and still be able to get enough wheel speed to bump ledges in second or 3 th gear.
The 6 speed gives a nice gear spread to scream up sand hills also

I think the magic number for the trails is around 100:1.  More is OK but can be slow for the flatter parts.  Less and you'll struggle a little in the rock gardens.

I'm trying to be realistic with my goals and expectations which is one of the reason's I think the 2spd is a better choice.  Also, I agree that $1000 could be better spent elsewhere.

[aw12345]

my 120:1 and 5.38 gears churns the 40" tires just fine and in low range I can still run  20 mph in 6 th and low range while the squirels are screaming at 4 grand.
FRom what I saw in the gearing calculator when I looked at your setup you would pretty much come out the same with 4.56 gears and 33" tires I think your crawl ratio with a 5:1 Atlas will come out to 90:1 and you can get close to 20 mph in low range at 4K .  Looking at the gear ratios 5 th gear low range would just be a tad lower than 1 st in high range which to me is ideal. When ofroading a lot of the hills are a bit much in 1 st in high range and 5 th in lo range would give you just that little extra but is still high enough that you do not constantly have to shift between low range and hi range. Which to me with my terra lo was a pain in the rear

[neale_rs]

Realistic is just skipping the Atlas. You've already driven the Rubicon without one. An Atlas is not about being realistic (it's actually extreme and extravagant, ask any normal person  ), it's about getting what you want.  The cost difference will soon be long forgotten. 

[aw12345]

That is why the 6 speed would be a very nice addition it takes the big step between gears away, combined with a good transfercase makes a very nice and plenty versatile setup that is still simple and very reliable

[Jeffy]

Realistic is just skipping the Atlas. You've already driven the Rubicon without one. An Atlas is not about being realistic (it's actually extreme and extravagant, ask any normal person  ), it's about getting what you want.  The cost difference will soon be long forgotten.  

Actually that wouldn't be realistic for me at least.  I don't want to spend too much money.  OK $2K is a lot but I've been wanting to do this for decades, literally.  I've held off spending any money on the powertain just so I could figure out what I wanted.  Though, I don't think I'll ever buy another Jeep unless one is given to me. (which is possible since I've been given an offer.)  But I don't really like the new Jeeps.  For the money, I don't think they are worth it.  If I want more comfort, I'll get a car, which I'm also working on.

One of the nice things about the Atlas is that I can change the input shaft (actually I'm not sure if they sell them to customers,  last I checked it was $200 for them to swap it) and put it on a different transmission.  I've got a few different ideas that I'd like to someday try.  Then again, if I replace the transfer case and fix some little things, I could theoretically be done.

[FourbangerYJ]

Really the 4.3 should do about everything you want to do. First time I did the Dusy I was on 33's and a 4:1. It did OK. But there were times I wished for lower ratio to grab. Most of the wheeling I do is in the 4:1 range. I rarely use just the 2.46 alone, and rarely use both boxes together. But I am glad I have the choice if the need is there.
After having just a 4:1 first, then upgrading to 2 boxes I can't see only having one box. Yes it does cost more by a fair amount to me it was worth it and I would do it again. Like Neale said you soon forget the cost after a while.

But if you really boil down to what you need the 4.3 should be just about right for most situations.

[Jeffy]

Really the 4.3 should do about everything you want to do. First time I did the Dusy I was on 33's and a 4:1. It did OK. But there were times I wished for lower ratio to grab. Most of the wheeling I do is in the 4:1 range. I rarely use just the 2.46 alone, and rarely use both boxes together. But I am glad I have the choice if the need is there.
After having just a 4:1 first, then upgrading to 2 boxes I can't see only having one box. Yes it does cost more by a fair amount to me it was worth it and I would do it again. Like Neale said you soon forget the cost after a while.

But if you really boil down to what you need the 4.3 should be just about right for most situations.

I think I'll probably go with 5.0:1.  Seems to be just enough lower then 4:0 to be worth it but not really too low.  For the price of a 4.3:1 it might be better to find a used NVG241OR and NV3550.

I've got a few scenarios planned out.  The Atlas 5.0 would be the cheapest.  I like the simplicity and dependability of my current setup.  Just need to change the transfer case though.  The slip yoke is making noise when I let off at speed.  Would maybe like to go deeper on the axle gears but that's Stage 2.