tcase doublers?

[jared]

i have been hearing about transfer case doublers lately the np231 to another 231. this seems like an interesting setup to me.

 

does anyone have info on how this works, like how you shift them into low range, or would it work with like a tera low 4:1 and the factory 2.7 in the other, to get a nice range in gearing.

 

benefits to this setup compared to say an atlas?

[beaterjeep]

benefits to this setup compared to say an atlas?

Cost is one huge benefit. 231's are a plenty and relatively cheap. :D

[Kenosha Warrior]

normally you do a twinstick. Its doable, maybe some adapter plates to buy but thats it. I was considering doing one up for when the XJ goes trail only.

[xjcrazy09]

is this considered a cheap tcase mod by doubling two np231s?

[Motion Offroad]

I know of 2 kits currently on the market for doubling the 231. They are the Madrooster Offroad Kit and the DD Machine Box4Rocks kit.

 

The Box4Rocks kit is defiantly a nice setup. We used it with a Dana 300 / NP231 doubler combo. Worked perfectly.

 

The Box4Rocks kit I believe runs right at $399, where the Madrooster kit is more expensive at around $100 more. As to why one is better than the other I have no clue as I've not researched them in depth.

 

As far as getting them, here is the info I can provide for you.

 

D.D. Machine (ask for Duffy)

(360) 779-2500

dd98370@hotmail.com

(I believe he has Yahoo Msg. as well under the name of djld98370)

 

 

Madrooster Off Road (ask for Phil)

(559) 232-5566

madroosterfab@yahoo.com or desertcj2002@yahoo.com

(I believe he has AOL Msg. as well under the name of ieffed)

[xjcrazy09]

would be cheaper to buy a doubler kit for a np231 or to build a d300 with a twin stick and lower tcase gears? what are the advantages of a doubler kit?

[MiNi Beast]

would be cheaper to buy a doubler kit for a np231 or to build a d300 with a twin stick and lower tcase gears? what are the advantages of a doubler kit?

 

231 are easier and cheaper to come buy.

 

I'll look but I just saw a tread where A guy did a write up on his doubler setup.

http://www.petrisimolin.com/ThePalsta/t ... C_ID=26100

http://www.naxja.org/forum/showthread.p ... 31+doubler

http://www.pirate4x4.com/articles/produ ... ad_rooster

[Motion Offroad]

Cost really depends on what you can find a Dana 300 for. If you can get a good deal on one your better off going that route (in my opinion).

 

You will have to run a flip kit on the Dana 300 though to fit it under your XJ/MJ.

[Geonovast]

Depends on how low you want your crawl ratio.

 

Actually just had this conversation with Jeepco last night.

 

Let's say you have an Ax-5, a Teralow 4:1 NP231, and 4.10s

 

3.93(1st gear) x 4 (low range) x 4.10(axle gearing) = 64.452:1 Crawl ratio.

 

Now with the same Ax-5, 4.10s, and dual regular NP 231s.

 

3.93(1st gear) x 2.72(low range) x 2.72(low range) x 4.10 = 119.21:1 Crawl ratio. (that's 3.8MPH at 5000 rpm with 31 inch tires by the way)

 

Another advantage to a doubler is you can run either 2.72 or 7.39 low range.

[A-man930]

The major advantages in my eyes are cost and gearing options... keep your highway gears (3:54s in my case) and have two low range options... for waaay less than an atlas or kluneV.

[Geonovast]

..OR you could spend a boatload of money and run 4:1 in one an stock 2.72 in the other for 3 low range options..

 

2.72, 4, or 10.88.

 

Which would change that crawl ratio from 119.21 to 175.3

[MiNi Beast]

:huh???: Way to much math for me.

[A-man930]

..OR you could spend a boatload of money and run 4:1 in one an stock 2.72 in the other for 3 low range options..

 

2.72, 4, or 10.88.

 

Which would change that crawl ratio from 119.21 to 175.3

:???: Uh, that's still only two ranges, just lower.

[Geonovast]

..OR you could spend a boatload of money and run 4:1 in one an stock 2.72 in the other for 3 low range options..

 

2.72, 4, or 10.88.

 

Which would change that crawl ratio from 119.21 to 175.3

:???: Uh, that's still only two ranges, just lower.

 

No, it's three. If the cases have different ratios, it gives you three options.

 

Say the front case has 2.72:1 and the rear has 4:1

 

With just the front case in Low, you have 2.72:1(2.72 x 1)

 

With the front case in HI and the rear in Low, you have 4:1(4 x 1)

 

With both in Low, you have 10.88:1(2.72 x 4)

[A-man930]

DOH! :wall: I knew that :roll: You would want to be carefull making the range case (the first one) the 4:1... thats allot of torque multiplication for that second case to handle.

[Geonovast]

It really wouldn't matter which one went where. I would put the 4:1 one up front though, simply for convienence. That way you wouldnt have to bother engaging two levers for normal(2.72) 4 Low. You'd only bother with the 4:1 stick if you really really needed it.

[xjcrazy09]

I am thinking about doing something with tcase gears or something...maybe get a little bit more crawl gear if i need it. In case i want to step up in tire size someday down the road.

[jared]

so with the doubler setup 231 to 231. how do you shift it now? is there custom linkage 2 levers or what?

[Geonovast]

I am thinking about doing something with tcase gears or something...maybe get a little bit more crawl gear if i need it. In case i want to step up in tire size someday down the road.

 

From what I've seen, re-gearing axles is a lot cheaper than doing a T-case. I've been told Teralow 4:1 T-case gears can run upwards of $1000.

 

so with the doubler setup 231 to 231. how do you shift it now? is there custom linkage 2 levers or what?

 

You'd have to. The lever for the rear case would be your standard 2HI - 4HI - N - 4LO, and the front case would just be HI - N - LO.

 

Just to offset any confusion, I am not running a dual case setup.

[xjcrazy09]

well I have already done 4.56 regear in the axles. I really like the 4:1 tcase that allows you to still have decent highway speed.

[Geonovast]

Regardless of what T-case gears you use your highway mileage is going to be the same, since they all have 1:1 HI Range.

[xjcrazy09]

ohh thanks for clearing that up for me

[pingpong]

The main advantage of any doubler is to have choices. sometimes you need speed and rpm's (mud/sand) to make it through other times you want your tires to barely turn( rock crawling). That being said.. if I was looking at doing the 231 doubler the box for rocks is the ticket... Mad rooster was the first setup out there, but it is super pricey. If you are deciding to do this on a price choice.. don't forget to factor in the cost of adapting a shifter for the second t-case... I believe you can use your existing mounting setup for the range box. Also keep in mind you will need to build some sort of t-case support/ belly skid. NOvak makes a t-case shifter for wranglers that is reasonable and doesn't require the use of the body as a pivot point.

 

 

On my rig I went with a doubler, but since I am running a chevy drivetrain, I went with a np203/d300. The advantage of this setup for me was t-cases were free :D and I have the ability to run a twin stick, and upgrade the outputs to 32 spline :brows: and if I find that my gear choices aren't low enough, I can install a 4 to 1 kit in the d300 :nuts: My doubler setup weighs with adapters well over 100LBS so if this is a factor don't even think of it

 

The np231/d300 doubler is stupid expensive by the time you factor in the cost of the cases (unless you get a deal like me), the cost of the doubler, and flip kit... then there is still shifters, and x-members to think of.