Atlas 4 vs Dual Cases

[AssBurns]

Obviously dual cases will be cheaper, but is the Atlas 4 speed worth the extra cost?
I guess that depends on the goals of the vehicle, right? I'd think a cheaper, low HP rig with large tires could really benefit from the cost and low gearing options of dual cases. However, my long term goal is to build something that can bomb through the desert as well as it can play in the rocks. So my thought process is to get an Altas 4 Speed with the 1.0:1 / 2.72:1 / 1.50:1 / 4.08:1 gearing options. I'd think that having the 1.5:1 ratio would be extremely beneficial when bombing through the hills and washes of places like Ocotillo Wells/Truckhaven where you don't really get much more than 45 mph, but still want to go faster than what a standard low range can offer. Then you have the standard low range of 2.72:1 for the basic low range trails, and 4.08:1 for the technical trails. Obviously it would be pretty nice to have lower than 4.08:1, but I feel the tradeoff of having both the 1.50:1 and 4.08:1 would outweigh the lack of having super low gearing of dual cases with a 4.7 case. Both Altas 4 and Dual Cases are clockable to achieve a flat belly.

Whatcha guys think? Worth it, or not in this situation? Good thing I don't have the funds to do this right now, so I have plenty of time to decide.

 

[RPS1030]

Some initial pros...

Dual cases can be done in stages...
Duals
4.7s in the rear
Shifters
Upgraded internals

At that point, you’re getting into full Atlas cost territory.

Atlas gives you all the gearing options on ordering. Also front dig ability.

I’ve run 2 different 22r(e)/5 speed based rigs on similar sized tires.

Buggy has 2.28/4.7 duals and 4.10s in the axles
4Runner has a single 4.7 and 5.29s

Buggy is stupid slow in low-low. Most crawling is in 3rd gear and slow stuff is in 2nd. But having the 2.28 saves the day for getting from the trailhead to the trail.

4Runner has been slow enough so far. Just a little more would be great. But not having the split is annoying. Slow road is a lot of 1st and 2nd gear high range.

My first choice on a budget would be duals in stock ratios and preferably geared axles. 2.28x2.28 is lower than 4.7 and gives you the split.

Edit: I’d personally go to at least the next step of 5.44 if geared in the axles or auto or more power. 8.16 would probably be my first choice for the buggy.

 

[4runner DOA]

I heard you have some time to save up because some big company bought up all the aluminum in the country. Marlin is gonna be backed up for awhile.

Either way, I'll probably just got with a crawl box when I've got a spare 4k floating around. Be awhile myself though unless my ex suddenly clears up the back support she owes me.

 

[theesotericone]

I looked long and hard at Atlas before I decided on duals. Cost wasn't the main factor for my decision. A big part is getting the Atlas to fit. With your fab skills that shouldn't be too much of a problem though. My biggest reason for going with duals was the ability to pull them if they break and easily throw my old case and shafts back in. And I mean easily. There was no moving of cross members for my duals. I can drop them and have the stock case back in with no extra work. I also went 2.28/2.57 cause I'm an auto. That's a final at the cases of 5.85. You've seen my rig crawl so you know what that's like. 4.08 is pretty high if you really want the crawl control.

It's your rig and I know you'll choose what suits you best. Either way you'll be stoked.

 

[AssBurns]

I heard you have some time to save up because some big company bought up all the aluminum in the country. Marlin is gonna be backed up for awhile.

Either way, I'll probably just got with a crawl box when I've got a spare 4k floating around. Be awhile myself though unless my ex suddenly clears up the back support she owes me.

Yeah definitely not in a rush. I’d rather do LT first.

I looked long and hard at Atlas before I decided on duals. Cost wasn't the main factor for my decision. A big part is getting the Atlas to fit. With your fab skills that shouldn't be too much of a problem though. My biggest reason for going with duals was the ability to pull them if they break and easily throw my old case and shafts back in. And I mean easily. There was no moving of cross members for my duals. I can drop them and have the stock case back in with no extra work. I also went 2.28/2.57 cause I'm an auto. That's a final at the cases of 5.85. You've seen my rig crawl so you know what that's like. 4.08 is pretty high if you really want the crawl control.

It's your rig and I know you'll choose what suits you best. Either way you'll be stoked.

Unless I do a v8 swap, I need more torque to bomb through the desert at mid speed. I’d say 70% of my offroading could benefit from a 1.5:1 ratio without a motor swap. It would kinda suck to be limited to a 4.08:1 crawl ratio, but if I stick with 35’s and 5.29’s, I think it’ll be plenty fine. Just won’t be as low as yours. I think it’ll be a win/win without swapping engines. Plus the ability to front dig is fucking awesome!
Any idea what the total length of your cases are from transmission mounting surface to driveshaft flange surface? That’s something else I need to consider to keep my DS angles happy at high speeds and high travel numbers.

 

[Blender]

I looked long and hard at Atlas before I decided on duals. Cost wasn't the main factor for my decision. A big part is getting the Atlas to fit. With your fab skills that shouldn't be too much of a problem though. My biggest reason for going with duals was the ability to pull them if they break and easily throw my old case and shafts back in. And I mean easily. There was no moving of cross members for my duals. I can drop them and have the stock case back in with no extra work. I also went 2.28/2.57 cause I'm an auto. That's a final at the cases of 5.85. You've seen my rig crawl so you know what that's like. 4.08 is pretty high if you really want the crawl control.

It's your rig and I know you'll choose what suits you best. Either way you'll be stoked.

So how is the 2.28 crawler? Im interested but hung up on ratios. Marlin says 4.7 in tje crawler no matter what which sounds crazy. My buddy who had a LT FJC ran 4.7 in the front case and loved it. Trying to apply logic indicates 2.28 in tjevfront case is plenty low for my use, but at the same time its pretty much a duplicate ratio as the stock 2.57.

Share some wisdom

 

[RPS1030]

So how is the 2.28 crawler? Im interested but hung up on ratios. Marlin says 4.7 in tje crawler no matter what which sounds crazy. My buddy who had a LT FJC ran 4.7 in the front case and loved it. Trying to apply logic indicates 2.28 in tjevfront case is plenty low for my use, but at the same time its pretty much a duplicate ratio as the stock 2.57.

Share some wisdom

Not sure if I’ve said it in other conversations...

I wouldn’t be too hung up on “2 same/similar ratios”. If double low is where you want to be, run it. Going crazy low in the front does increase the stress on the input to the rear case.

 

[Blender]

Not sure if I’ve said it in other conversations...

I wouldn’t be too hung up on “2 same/similar ratios”. If double low is where you want to be, run it. Going crazy low in the front does increase the stress on the input to the rear case.

That ties in with my original want. Three ratios: 1:1 , 2.57:1 and an unknown crawl gear.

 

[Blender]

@RPS1030

The added torque on the stock input is my main concern on the 4.7 in the front case. I dont mind if stuff breaks, but i dont wanna purposely set parts up to fail

 

[AssBurns]

That ties in with my original want. Three ratios: 1:1 , 2.57:1 and an unknown crawl gear.

It would actually give you 4 ratios, right? The benefit of having 4.7 is to have 1:1, 2.57:1, 4.70:1, and 12.079:1 crawl ratio that is super low. i'd think the ultra low crawl ratio is only needed on larger tires and very little hp.

 

[Blender]

It would actually give you 4 ratios, right? The benefit of having 4.7 is to have 1:1, 2.57:1, 4.70:1, and 12.079:1 crawl ratio that is super low. i'd think the ultra low crawl ratio is only needed on larger tires and very little hp.

Yes. The point being 2.23in the front case and stock 2.57 are so close they are pretty much the same. A front case with 4.7 does give me 4 distinct ratios although not all are really needed in my mind atleast.

With an auto and V8 i dont think i need 10:1, but have been told ill find use for it. I do have the handicap of only a4 speed auto. Really only a three speed since OD is locked out while in low range.

Or just buy one and be happy

 

[RPS1030]

That ties in with my original want. Three ratios: 1:1 , 2.57:1 and an unknown crawl gear.

My first choice would be dual stock cases with triple sticks in my rigs.

Hit the dirt and put the rear case in low range. Need to crawl, shift the crawl box into low. Back on the 2-track, shift the crawl box back to high and have just the rear case in low again. If I’m winding it out, shift the rear case back into high.

Adding 4.7 to the rear case is great, but now everything gets shifted at the same time. Crawl box in low, get to the rocks and shift it to high and rear case to low.

Just occasionally in double low for crazy stuff. Gearing the axles would eliminate that use.

 

[RPS1030]

Yes. The point being 2.23in the front case and stock 2.57 are so close they are pretty much the same. A front case with 4.7 does give me 4 distinct ratios although not all are really needed in my mind atleast.

With an auto and V8 i dont think i need 10:1, but have been told ill find use for it. I do have the handicap of only a4 speed auto. Really only a three speed since OD is locked out while in low range.

Or just buy one and be happy

If you aren’t already, going any lower is going to drive right thru the brakes. Going to have to get used to popping it into neutral quickly.

 

[Blender]

My first choice would be dual stock cases with triple sticks in my rigs.

Hit the dirt and put the rear case in low range. Need to crawl, shift the crawl box into low. Back on the 2-track, shift the crawl box back to high and have just the rear case in low again. If I’m winding it out, shift the rear case back into high.

Adding 4.7 to the rear case is great, but now everything gets shifted at the same time. Crawl box in low, get to the rocks and shift it to high and rear case to low.

Just occasionally in double low for crazy stuff. Gearing the axles would eliminate that use.

Thats pretty much my workflow. Since im keeping all the electronic xfer case shift id rather just single lever compound low

 

[Blender]

If you aren’t already, going any lower is going to drive right thru the brakes. Going to have to get used to popping it into neutral quickly.

Currently the brakes hold in low with 4:56 axle gears. I expect to power through them in compound low though

 

[Blender]

Well decision made. Ill order this crap after moab, then wait forever

 

[AssBurns]

Yeah if you have an auto, there is no need for 4.7 case. @theesotericone has a 3.4 Auto with dual stock cases, and his is plenty low. I wouldn't see a need to go any lower or have more combos to choose from.

 

[theesotericone]

So how is the 2.28 crawler? Im interested but hung up on ratios. Marlin says 4.7 in tje crawler no matter what which sounds crazy. My buddy who had a LT FJC ran 4.7 in the front case and loved it. Trying to apply logic indicates 2.28 in the front case is plenty low for my use, but at the same time its pretty much a duplicate ratio as the stock 2.57.

Share some wisdom

A lot of this has been touched on but I'll give you my advice.

If your rigs a manual go with the 4.7's in the crawlbox.

If your rigs an auto go with 2.28(stock) in the crawlbox.

With a manual you also have 5 speeds(gear ratios) to choose from, So you want your crawl ratio as low as you can get it. Then you can choose to shift into lo/lo and use 2nd or 3rd if needed.

If your an auto you really only have first gear when crawling. I can get into 2nd and 3rd in lo/lo but it's easier to shift the crawlbox back to high. What you also have in an auto is a torque converter. That effectively doubles your crawl ratio.

In my case I'm an auto with 5.29's. To find the crawl ratio you do:

Trans ratio x Crawlbox x Stock t-case x axle ratio:

2.804 x 2.28 x 2.57 x 5.29 = 86.91

With my torque converter that effectively gives me a final crawl ratio of 173.83.

That's plenty low and I'm glad I saved the 500 bucks on the 4.7's. If your a manual it won't be low enough and you'll wish you spent the money on the 4.7's.

 

[eimkeith]

I'm glad I read that!

 

[4Running Daily]

I looked long and hard at Atlas before I decided on duals. Cost wasn't the main factor for my decision. A big part is getting the Atlas to fit. With your fab skills that shouldn't be too much of a problem though. My biggest reason for going with duals was the ability to pull them if they break and easily throw my old case and shafts back in. And I mean easily. There was no moving of cross members for my duals. I can drop them and have the stock case back in with no extra work. I also went 2.28/2.57 cause I'm an auto. That's a final at the cases of 5.85. You've seen my rig crawl so you know what that's like. 4.08 is pretty high if you really want the crawl control.

It's your rig and I know you'll choose what suits you best. Either way you'll be stoked.

Request pictures of your crossmembers

A lot of this has been touched on but I'll give you my advice.

If your rigs a manual go with the 4.7's in the crawlbox.

If your rigs an auto go with 2.28(stock) in the crawlbox.

With a manual you also have 5 speeds(gear ratios) to choose from, So you want your crawl ratio as low as you can get it. Then you can choose to shift into lo/lo and use 2nd or 3rd if needed.

If your an auto you really only have first gear when crawling. I can get into 2nd and 3rd in lo/lo but it's easier to shift the crawlbox back to high. What you also have in an auto is a torque converter. That effectively doubles your crawl ratio.

In my case I'm an auto with 5.29's. To find the crawl ratio you do:

Trans ratio x Crawlbox x Stock t-case x axle ratio:

2.804 x 2.28 x 2.57 x 5.29 = 86.91

With my torque converter that effectively gives me a final crawl ratio of 173.83.

That's plenty low and I'm glad I saved the 500 bucks on the 4.7's. If your a manual it won't be low enough and you'll wish you spent the money on the 4.7's.

I'm glad I have 4.7's in my Marlin Box. Just need to install it.

For now she shall rest
Untitled by Connor Rhoades, on Flickr