Explain dual cases to me

[DUDELUX]

Im toying with the idea of fitting dual cases to my Lux. I have a front shift in the Lux now, and also have a top shift in the shed.
I understand that low low range will give me a super controlable low crawl speed, which will be nice to have, especially in descents.
I love my low range now, and dont want to run reduction gears, as Ill miss my low range, so Im thinking about going duals.

The thing I dont understand is, why run the other combinations of gears, high low, low high, low 2wd, etc??

Please explain the need of these other gear combinations, or their likely uses.

As for fitting it, I know Ill need some sort of adaptor to join the cases together, custom crossmember, custom driveshafts, and chromo output and input shafts.

Waiting for knowledge now.

Fanks

[rockcrawler31]

well for a start you can have two different ratios in the transfers. Say 2:1 in the front and 3:1 in the rear. so realistically you have options of 2:1, 3:1 or 6:1.

If your two transfers have the same gearing you only have the one intermidiate gearing regardless of whether it's low/high, or high/low selected.

I think that short of a 4 speed atlas, duals is the way forward. there's times that a deep low sucks when you need a bit of wheel speed and HP to bump over stuff. but for crawling you want your slow deep reduction. I'm stuck with 5:1 in my atlas and i'd love an intermidiate gear

[GUtripper]

Never run them.
But logic says you achieve normal low range by shifting either case into low. Actually, scratch that. The rear output off the front case would drive the input on the rear case.
Super low by moving them both into low.
Never had a lux, but assuming the cases are either rwd only or fwd, maybe there's some set up whereby your could run front and rear driveshafts alone or together? Ie, do a dig with the front only?

If you drove the front axle via the output on the front case, there is potential to have the front in high and the rear in low. Which you wouldn't want I guess.
But you could still do a dig that way, by shifting the rear case ( which drives the rear axle) into neutral.

Damn. My brain now hurts.
Buy an atlas with whatever low reduction you want.

[turps]

I always thought that there is 2 parts to a transfer case atleast on a patrol there is.
They have the range selector (High or Low). which then bolts to the transfer case which selects 2wd & 4wd.
So there is an adaptor made by marks4wd to bolt 2 range selctors together.


So guessing that if a lux is the same. Then you can only have one set of outputs for drive shafts. So no chance of sending high range to one end and low to the other.

And for lux gear there a couple of options to join together. Only one I can think of hand is Marlin crawler, but I am sure lockt up do one also.

[mico]

Never run them.
But logic says you achieve normal low range by shifting either case into low. Actually, scratch that. The rear output off the front case would drive the input on the rear case.
Super low by moving them both into low.
Never had a lux, but assuming the cases are either rwd only or fwd, maybe there's some set up whereby your could run front and rear driveshafts alone or together? Ie, do a dig with the front only?

If you drove the front axle via the output on the front case, there is potential to have the front in high and the rear in low. Which you wouldn't want I guess.
But you could still do a dig that way, by shifting the rear case ( which drives the rear axle) into neutral.

Damn. My brain now hurts.
Buy an atlas with whatever low reduction you want.

The Hilux cases are 2 piece, the front piece has the reductions gearing in it and the rear piece has the outputs (and the 4wd activation I think...).
Duals are made by adapting the front of the front caseto the front of the second case if that makes sense (you really only use 1 1/2 cases)

Geez I type slow Turps beat me by a bit in his reply

[WICKED]

I have a 4spd atlas and have 1:1, 2:1, 2.72:1 an 5.44:1.

5.44 is amazing in rocks ie tuff truck but I found it was too low to have wheel speed in sand, gravel and crap like that. Was wheeling and got stuck on a slight rutted gravel incline with a step. Your lux would have crawled it piss easy. I put it in 2.72 and did it easy.
It's just about having the option to chose the gear that will work best in that situation.

[DUDELUX]

Not running an atlas. Its still a daily.
Ive got the top shift case here, it is on the back of the gearbox I bought before tuff truck, and when I got it home, I thought of duals. Im only now seriously considering it.

I can have the front case in low, and the rear case in neutral, and be in low range, so I can crawl like I do now. I can then put the rear case into low aswell, and be in low low range, and crawl really slow.
Is this right??

So does high high, high low, etc do anything, or are they pointless??

So apart from gaining an extra low range, is it really worth all the work to set them up??

[rockcrawler31]

We weren't suggesting you get an atlas, what we were saying is that the duals give you a second "transmission" instead of just high and low range. Yes i agree they are worth it as long as packaging isn't too much of a headfuck. What both me and Wicked were saying was that rather than having a single super deep reduction on ONLY that choice in a single transfer case, this gives you the option of several reduction values.

A normal low range for general work and when you need wheel speed to bump over stuff
a semi deep for more control
super deep for crawling.

So a single transfer will let you choose ONE of those options but not both. And what i was saying was that if you choose the reduction ratios in the transfers properly, you don't get two reduction ratios, you get THREE depending which one of the transfers is in low range.

So the summary is that twins is not about achieving a super deep reduction, it's about FLEXIBIITY.

Also, the above posts are correct, you are only doubling the forward part of the tcase that has the reduction gearing not the bit that provides the forward output.

[r0ck_m0nkey]

I can have the front case in low, and the rear case in neutral, and be in low range, so I can crawl like I do now.

No, you would be in neutral. The front case, really only becomes an additional 2 speed gearbox in between the gearbox and transfer case, to give as others have said, more options.

I can then put the rear case into low aswell, and be in low low range, and crawl really slow.
Is this right??

So does high high, high low, etc do anything, or are they pointless??

So apart from gaining an extra low range, is it really worth all the work to set them up??

With standard gearing, you do get some cross over in options, say for instance Low/4High will be the same as High/4Low. You essentially have only 3 gear options, High Range, Low Range and Double Low. If you throw in a set of reduction gears into one of the cases, you open up other options.

Just to show what they will do, you could have the following options. Standard gearing in both cases in white, Standard in front case and 4.7 reduction in rear in red, and 4.7 in front with standard gearing in rear in yellow

high / 2 high - High Range 2WD - (1:1)(1:1)(1:1)
high / 4 high - High Range 4WD - (1:1)(1:1)(1:1)
high / 4 low - Low Range 4WD - (2.28:1)(4.7:1)(2.28:1)
low / 2 high - Low Range 2WD - (2.28:1)(2.28:1)(4.7:1)
low / 4 high - Low Range 4WD - (2.28:1)(2.28:1)(4.7:1)
low / 4 low - Double Low 4WD - (5.2:1)(10.7:1)(10.7:1)

Think I got that all right.

[Scott]

I've had dual cases and one of the main benefits is you get normal low for cruising around bush tracks, then get to something real hard you can shift into low-low and have the benefit of crawler gears. I wouldn't worry about the all the gear combinations, use low-low in real hard stuff, then shift back into normal low when through it.

As others have said, the front case only has the reduction gears. The kit should come with a small piece of steel you weld onto the high-low shift rod, locking the shift lever into that side so it only goes back and forward, between high and low.

As for chromo inputs and outputs, I didn't have them and had no issues. I probably don't drive as hard as others, no comp work but my Hilux had a commo V6 and 35s and it held up fine.

[Baja Burley]

When I was looking into I found duals to be the more expensive option (excluding cost of extra Tcase because I already have one) I have an auto though, which crawls awesome in normal low.

Reduc gear are also an easier install, whether you or a pro does it...

Keep in mind you have your normal gearbox to work with too. So when in reduction low (4.7:1) in the Tcase. You still have 2nd and even 3rd gear in your regular gearbox to use if 1st low is too slow.

Some call it "snapping 2nd". Haha.

[DUDELUX]

Thats some awesome info right there. Thanks a bunch guys.
With the graph above, of all the crawl ratios. Any idea what it is now, running single case?? Just so I can compare it to the numbers above.
It seems as though I wont need to run reduction gears in one of the cases, maybe further down the track if I see the need for them.

Please correct me if this is wrong....
If I fit duals, the front case can no longer select either 2 or 4wd, only high or low range.
Driving everyday would still be high/high2.
Normal offroad would be high/high4.
High/low4 or low/high4 for fun stuff(low range).
Low/low4 for hard stuff(low low range).

Im only running a 2.4diesel motor, will be turboed eventually. Will never run more than 9psi on it, so wont be a powerhouse. Do you think Ill need chromo output/input shafts.

Again, all the info is greatly appreciated, so thanks guys.

[DUDELUX]

Just wondering where youd use Low range 2wd.

[SierraDan]

For me, 2L is good for having low range but not putting torque to the front auto locker, so I can manoeuvre around without heavy steering.

It's more the flexible reduction options you should be thinking about with twin transfer than the 2L.

I will be making something for my Sierra, which will allow me four options for several terrains and the road as Sierra cases have reduction in High.

[SierraDan]

Please correct me if this is wrong....
If I fit duals, the front case can no longer select either 2 or 4wd, only high or low range. Yes
Driving everyday would still be high/high2. Yes
Normal offroad would be high/high4. Yes
High/low4 or low/high4 for fun stuff(low range). Yes
Low/low4 for hard stuff(low low range). Yes
.

Everything will be the same, except you will have an extra low range option and stick in the tunnel.

[Scott]

When I was looking into I found duals to be the more expensive option (excluding cost of extra Tcase because I already have one)

I'd agree with that. Definitely more expensive and complicated to install duals. Once you've got the dual adapter and t-case, modifying drive shafts will be the main expense, plus the cross member. You'll also need to extend the speedo cable.

When I did mine, drive shafts was the most expensive part, but I did get a long spline front shaft. Maybe I paid too much, but if money is tight, it might be worth checking first so you don't get a rude shock.

[turps]

Just wondering where youd use Low range 2wd.

If you tow its great for back trailers or caravans on hardpack surfaces. My dad does it all the time in his 80series.

In your case I am guessing not real useful. Its just an option that running dual cases allows.

[80's_delirious]

to add to what rockmonkey has listed, take into consideration diff gearing and gearbox gearing too.
Your standard lux gearing will give you approx a 40:1 final crawl ratio(i dont know the diff or 1st gear ratio to get it exact).
with duals, both with standard gearing you'll get approx 85:1 final crawl ratio
with 4.7 gears in one case, you'll get approx 170:1 fina crawl ratio

at 40:1 on 35's you'd travel approximately 70metres/minute at 1000RPM (engine revs)
at 85:1 on 35's you'd travel approximately 30metres/minute at 1000RPM
at 170:1 on 35's you'd travel approximately 16metres/minute at 1000RPM

do a pootube search for "walking the crawler" to see a lux traveling at about a 200:1 crawl ratio with the driver walking besdie it
or chatting to his buddies

Just to show what they will do, you could have the following options. Standard gearing in both cases in white, Standard in front case and 4.7 reduction in rear in red, and 4.7 in front with standard gearing in rear in yellow

high / 2 high - High Range 2WD - (1:1)(1:1)(1:1)
high / 4 high - High Range 4WD - (1:1)(1:1)(1:1)
high / 4 low - Low Range 4WD - (2.28:1)(4.7:1)(2.28:1)
low / 2 high - Low Range 2WD - (2.28:1)(2.28:1)(4.7:1)
low / 4 high - Low Range 4WD - (2.28:1)(2.28:1)(4.7:1)
low / 4 low - Double Low 4WD - (5.2:1)(10.7:1)(10.7:1)

Think I got that all right.

EDIT: pootube linkage. its at 128:1, but I believe 1ST/LOW/LOW gives him around 200:1?

http://www.youtube.com/watch?v=vZFLaX4J8fg

[Baja Burley]

That truck is Marlins from marlin crawlers and actually has 3 transfer cases. His low low low is close to 1000:1 iirc!! Lunatic!! He's in like 16th gear in that video. Epic wheeling.

It's a tonne of fab work to fit duals, but it gives wicked flexibility in crawling speed. But if your keen on spinning spanners on the thing and experimenting Then make sure you write it all up!! I can't see duals costing any less than 1k that's including a free second case.

Gears will come in a few hunj cheaper but with less flexibility as mentioned.

At the end of the day, mods come down to what you WANT, not need. Haha. No one needs anything on their cars. It's all a big want. Haha!

[brad 93hilux]

Most of it has been covered as I'm going duels now but here is a couple of links u can look at which may tell you something else you didn't hear.

http://www.locktup4x4.com.au/blog/dual- ... crawl-box/" onclick="window.open(this.href);return false;

http://www.hilux4x4.co.za/dual-transfer ... /index.php" onclick="window.open(this.href);return false;

Pretty good write up..
Brad

[SierraDan]

That truck is Marlins from marlin crawlers and actually has 3 transfer cases. His low low low is close to 1000:1 iirc!! Lunatic!! He's in like 16th gear in that video. Epic wheeling.

It's 1372:1 in first. 11th gear in that video at 128:1

Its ridicuous. The guy has a chart so he can figure out what gear he is in. It's more a show of acheivement than a good idea.

Even this at 511:1 is cool to watch, but you'd be on a single climb for a whole day.
http://www.youtube.com/watch?v=6LoQTme51tA" onclick="window.open(this.href);return false;

I've seen a few dual cases with standard gearing in both. It is plenty low for DUDELUX's driving i reckon.

[specs]

Duals with standard gearing 2.28 will give u approximately 10% lower than a single case with 4.7 reductions yet still give u standard 4 low which is lost with a single case with 4.7 reductions. U then have the option of 4 forward gear ratios and 228.1 or similar depending on diff ratios with a dual case set up with 4.7s in the rear case.

[brad 93hilux]

Yeh I worked out with my g52 twin transfers with one 4.7 case and 4.88 diffs I get 201-1 which compared to my single case at 4.1 crawlers i currently have approx 70.1 reduction..

I like the idea of having a 2.28 case and a 4.7 case to be able to choose either one gear ratio or in a comp i can select low low and combine the two..

This is my next mod (apart from fixing broken g52)

Brad

[dv8666]

So what sort of price difference is there between dual transfers and an atlas 4 speed conversion? Assuming it's a GU patrol.
The atlas has cable shift to make shifter location easier, with dual transfers you are locked into the shifter positions, correct?

[Baja Burley]

That is correct regarding shifter position. Although you aren't LOCKED IN with shifter position its pretty difficult to change. You can fab linkages and bent sticks and all that jazz but thats alot of fucking around.

regarding your Nissan specific question... you're in a room of yota boys on this thread. haha. Marks do a dual case adapter..

[old lux]

So other then getting drive shafts extended. A new cross member the adapter kit and a front shift kit. Anything else recommended? I plan on run 4.7 in the rear case. Also does anyone know what percentage that is? As rock hopper have 111% reduction but don't say what ratio it is.

[DUDELUX]

Theres some numbers above, posted by Rock Monkey, and 80s Delirious. You could use them to maybe get an idea.