Dual transfer case

[AZ4x4]

So i used to own a Toyota and I had dual transfer cases in it. I was wondering if that was ever done in EBs. I have a NP-435 and just figured with the additional reduction of a second transfer case, my gear ratio would be super low. Thanks.

 

[langester]

I read a couple of posts here a while ago about a 203/205 doubler unit. Not sure about the specifics though.

 

[rockslut]

My little brother runs the 203/205 in his early bronco. We stretched the wheel base a few inches front and rear to help with drive line angles. Works supper good. I would do the same but i like my auto, and that would be a pretty long package.

 

[thegreatjustino]

203/205 is common

WH sells adapters to do a 203/Dana 20

http://www.wildhorses4x4.com/category/s?keyword=203

Klune makes a doubler box

Stak is another one that comes to mind

Years ago there was the Cold Duck which was two Dana 20s mated, but no longer made.

 

[nvrstuk]

I think back in the day the first dual case setup for a Bronco out of a Bronco D20 case was a Cold Duck (Jack OBrien)? or Marlin Dual Crawler setup... I put a ZF/203/D20 in my Bronco back in '00. This was years before AA or W/H had any ZF adapters... Gary Y came up with that design and the 435/203/D20 was starting to become more common around '02 or so. Then it broke loose with Greg Miller marketing the KluneV to fit many vehicle combinations and lot's of other combo's coming out... look at all the cool stuff we have now. I might be off on some stuff here but technology broke loose and we've all been spending our hard earned cash since!!

 

[gremlin]

I have c4/ marlin crawler/d20.

 

[sykanr0ng]

It's kind of older tech that has been passed by, these days the doublers are usually an aluminum housing with the planetary gears from a later model transfer case.
Smaller, lighter, better choice of gears (makes the final crawl ratio nearly triple).

Like this one:

http://www.northwestfab.com/NWF-BlackBox-Underdrive_c_7.html

 

[nvrstuk]

and b4 NWfab there was Luke at KluneV who is an amazing engineer...still drives a Bronco and runs a KluneV. I run a 4R70W/KluneV (2.7:1)/Atlas 4.3.

NWFab is doing some cool stuff too...

If ya got the $$$ now you can do about anything...technology just wasn't there 20 yrs ago...way before EB's were fetching 30K in decent shape...

 

[12-Pack Jeff]

How do you like your C4/Marlin/D20? My father recently picked up a used C4/Marlin/D20 setup and are in the process of installing it.

I also just acquired a KluneV for my rig. Unfortunately Klune's have not been for sale for quite some time. (C4/Klune/D20)

Good luck
12'r

I have c4/ marlin crawler/d20.

 

[nvrstuk]

When Greg Miller passed away, the Klune brand slowly fell off the market. Laurie (his wife) is still running the business but the Klune reduction boxes are a thing of the past. She still has some parts available if you ever needed something.

 

[ScanmanSteven]

I have one of the last Behemoths which uses a 1356 BW planetary gearset, between a ZF and 205. The rear driveshaft is 27" but with a limit strap works fine. A 203/205 combo gives a 4:1 low range and with you 435 at 6.69 makes for a super crawler. You should be able to fit a 203 to the 435 as Ford did that at one time but that might have been with an intermediate coupler/housing. One thing to keep in mind using the D20 in any doubler application is the out put shaft is a weak link. By the time you rectify that you might as well used a virtually unbreakable 205.

 

[Mountain Ram]

I have a NP241 doubler behind my C6. Basically the range box off the 241 in front of another 241. Worked in my full size ram crawler, so I figured it would work on the EB. Had to swap input gear for an NP271, but other than that, it bolted up! 2.72 & 7.4:1 low ranges as well as 2.72 2wd.

I also moved the rear back 10"... Would not come close in a stock WB Bronco.

 

[BRONKEN]

I have been running the cold duck unit since they were first conceived I think my set up was number 18 or so, it works great behind my C-4 with no issues.

 

[JWMcCrary]

I have been running the cold duck unit since they were first conceived I think my set up was number 18 or so, it works great behind my C-4 with no issues.

Same here, It works great. By putting the tera lows in the D20 you end up with 4 speeds with the lowest being 7.75 to 1 (2.46x3.15)
I like it, sometime the stock low range is all you need and it gives you a little more speed. By having the CD engaged and the D20 in high its the same as normal low range.

 

[Yeller]

I've run all kinds of different doubler set ups in the past. I've found that I prefer an auto to be about 40:1 in first gear with decent horse power (stock small block of your choice) to be just about perfect. Low enough to be in control and high enough to have speed when needed and I'm not fumbling to find the right gear. With a manual is where I find the doubler shines really low when you need that bit of super slow control but can swap around and get speed when needed

 

[edones06]

I run a c6 203/205 with the doubler parts come from northwest fab. I love it. Low gears for the rocks and a inbetween for the muddy days and the hills. I dont know if i could have another rig with out a doubler. But in my part of the woods really low gears only wouldnt be much help. . Its muddy round here. Some days just gotta have some wheel speed. My trans is also a manual valvebody with a engine brake in low gear. It really gives alot of control

 

[nvrstuk]

Even with my 418 stroker I run my KluneV engaged to keep my wheel speed up in deep snow. All 4, 37" tires are hard to turn when pushing heavy snow. I can keep them spinning at 45mph at a little over 5,000 rpm for a minute or two at a time in the deep stuff. Gas mileage drops a bit tho... lol

 

[gremlin]

I like the marlin crawler box it has 5.0 gears .

 

[garberz]

I've run all kinds of different doubler set ups in the past. I've found that I prefer an auto to be about 40:1 in first gear with decent horse power (stock small block of your choice) to be just about perfect. Low enough to be in control and high enough to have speed when needed and I'm not fumbling to find the right gear. With a manual is where I find the doubler shines really low when you need that bit of super slow control but can swap around and get speed when needed

Agreed! I run a C4, and my 1st gear ratio is about 48:1, but if I keep my foot on the brake I can cheat all the way up to 100:1.

Mark