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Duffy Box for Rocks 241 to 205 now...have a few questions.....

stallion85

stallion85

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I have been doing a lot of reading over on pirate on this box4rocks thing

http://www.pirate4x4.com/forum/showthread.php?t=456669

Right now I have a 32 spline 208 and a 32 spline 241. Looks like he still is not making the kit to work with the 208, but I could use the 231-to241. Now is the 231 trasfer case commonly found in S10 or S15's able to bolt to the back of my TH400? I don't know what trannys came in the little blazers, but if I could get a 231 to work I could get this kit which would only cost $400.

Anyone have any good news for me?

I believe the 231 is 2.72 low just like the 241. This would be a great inexpensive setup for my rig.................

If the 231 has the same bolt patter as all the other NP GM transfer cases it should bolt up after thinking about it. Now getting the 32 spline input shaft might be a chore. I wonder if the 208 input spline or 241 would fit into the 231?
 
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i dont believe the 231 had a 32spline input option, wasnt it behind the lighter duty trucks? anyway to swap in a 32input from a 241?
 
He also makes one to use a 241 as the box & can connect it to things. Use the 241 you have & put a 205 behind it and your set. I would be concerned about the 231's ability to hold up over time with diesel torque being put into it.

Harley
 
Jeff,

I have an S-10 231 sitting on the garage floor. I can fill you in on some of the stuff:

1) The bolt pattern to the adapter is different. It uses 5 bolts intead of 6.

2) This one has a 27 spline input. I'm guessing most did. I'm also guessing no such thing as a 32 unless a 208 input gear just happens to work. :dunno:

3) Seems to me you are considering running a 241 for the 2nd case..? I would not do this..... not in a >4000 lb rig I would run a 205.

Marv
 
Thanks for the heads up Marv. I will see if this guy makes one for the 241/205. I will give him a call and tell you guys the scoop.


Thanks,

Jeff
 
Well he responded over on my post on pirate. Here is what I asked:

stallion85 said:
Duffy, sorry if this has already been asked, but from what I have read can you tell me if this would work and your product supports it.
I have a TH400 to NP208 right now. If I find a 231 I can swap my 208 32 spline input gear to this one and use as the range box, then put my 32 spline 241 behind it? Also do you know what adaptor I would need to put the 231 behind my TH400? I want to order ASAP so I can have this done before the end of April.
Please PM me and let me know or email me [email protected]
Thank you,
Jeff
Click to expand...

Here is what he responded with:

d.d.machine said:
the 231 and 241 can swap the planitary. but the 208 is 100% different inside.
You well need to find a 241 drivers drop 32 spline to make into a box4rocks
but the upside is just run your 208 adapter to the crawl box and then the kit well go from the 241 to the second 241
( to run both boxes as drivers drop you well need to flip the crawl box so your front drive line well clear it ) simple redrill on two holes
Thanks
Duffy
D.D.Machine
(360)779-2500
Click to expand...


Now I could just get a drivers drop 241 which wouldn't be that hard.

Marv, why would you steer away from a 241 behind the crawler box? Is it a strength concern?

I know the cases themselves are fragile, but the internals look pretty beefy to me. Also I have a weak 6.2 so I would really like this to work.......
 
Even a pretty weak 6.2L with a 2.72 rockbox multiplying it is going to be a pretty healthy amount of power being put into the 2nd case. I would be worried about the 2nd case holding up to the power over time. Short term it would probably work ok but longterm would be a question in my mind.

The other issue is you are doubling the same gear. You don't offer yourself any gear options. With a 205 you are getting a 1:1, 2:1, 2.72:1, 5.44:1. With a 241/241 setup you get a better low low but you loose the 2:1 gear which is a great gear for crawlers to have available. The more gears available is better IMHO.

Harley
 
Lets say your 6.2L is capable of 250lbs of torque. Multiply that by the tranny 2.5ish = 575lbs x 2.72 crawl box = 1564lbs of input torque on the 2nd tcase. That is without any multiplication from the torque converter figured in.

1500+ lbs of torque is alot to ask from a 241. Even the beefier 241HD's in CTD's don't like that kind of power under hard use. Sled pullers are swapping in 271's because the 241HD's won't hack it when they are used for pulling. Granted your 6.2L probably won't be revving out to is max powerband but someday you might need to get on it in low low & you will be asking alot from the 2nd tcase when you do.

A 241's max input capacity is around 1000lbs continous. With a rockbox infront of it it will be at or above that limit without counting in torque converter mulitplication.

Harley
 
Originally Posted by d.d.machine;6391250
the 231 and 241 can swap the planitary. but the 208 is 100% different inside.
You well need to find a 241 drivers drop 32 spline to make into a box4rocks
but the upside is just run your 208 adapter to the crawl box and then the kit well go from the 241 to the second 241
( to run both boxes as drivers drop you well need to flip the crawl box so your front drive line well clear it ) simple redrill on two holes
Thanks
Duffy
D.D.Machine
(360)779-2500
Click to expand...

I thought you could swap the planetaries from 241s into 208s? This makes it sound like a 208 is an animal all its own?

Ira
 
yea the 208 is completely different from the 241. i looked into doing something similar, but ended up not doing itcuz that guy never posted pics of a complete finished product
 
muddybuddy said:
yea the 208 is completely different from the 241. i looked into doing something similar, but ended up not doing itcuz that guy never posted pics of a complete finished product
Click to expand...

I was pretty sure someone took a 241 plantary and put it in a 208.

Maybe I am loosing my mind and it is the painkillers talking:o

Ira
 
With 42's an 4.56 gears the 2.72 would be a be a decent normal trail riding gear. I know I am limiting my self with the 241 but it would be sick low. If I can get one of these I might be the guinea pig.

I just don't want to have to buy 2 transfer cases that was the whole push for this design....
 
Hossbaby50 said:
Lets say your 6.2L is capable of 250lbs of torque. Multiply that by the tranny 2.5ish = 575lbs x 2.72 crawl box = 1564lbs of input torque on the 2nd tcase. That is without any multiplication from the torque converter figured in.

1500+ lbs of torque is alot to ask from a 241. Even the beefier 241HD's in CTD's don't like that kind of power under hard use. Sled pullers are swapping in 271's because the 241HD's won't hack it when they are used for pulling. Granted your 6.2L probably won't be revving out to is max powerband but someday you might need to get on it in low low & you will be asking alot from the 2nd tcase when you do.

A 241's max input capacity is around 1000lbs continous. With a rockbox infront of it it will be at or above that limit without counting in torque converter mulitplication.

Harley
Click to expand...

Harley, what do you think the Jeep guys running this setup have for torque in there 6 cyl? Surely the newer Jeeps have that much torque. I wonder what the max input capacity is for the 205?

Then again most of them are running the 231 to Dana 300. The 300 is an all gear case too, right?
 
I believe that Jeep guys do run alot of Dana 300's which I believe are gear driven. I know they are basically a Jeep guys 205. Also remember that a Jeep is typically lighter then anything we wheel.

I would encourage you to try a 241/241 if you are willing to do it. Just keep in mind that if you are running single lowrange then you need to use the rear case in first. You must also keep in mind that you if you flog the hell out of it you may have problems.

The Jeep 6 cyl probably have as much torque as your diesel does but your diesel has 250lbs of torque from 1500-3000 rpm. Jeep guys won't hit that kind of torque till 2500+ Rpm most likely.

I would say go for it if you so inclined but just be aware of your driving techniques. Don't fall into the big dawg 1 ton mentality of I can flog the crap out of it all the time otherwise it could bite you in the arse big time.

It is worth a shot IMHO. Worst that happens is you bust a 241 apart & realize you need to get a 205 in there. You might see if you can find a Dodge 241 HD from a Cummins and see if you can run that behind your 241 rockbox. The 241 HD is rated for 1500lbs continuous input torque compared to a standard 241 @ 1000lbs. My main concern with the 241 is failure of the chain that drives the front output or bearing failures. The planetaries are probably strong enough but that front output chain is going to see ALOT of torque.

Harley
 
i did a search before on pbb, and there are some people running 231/d300 combo in their fullsize rigs, one was in a 1ton k5 on 40's and he said he hasnt had any problems. i believe there is a complete setup over there for sale right now for not alot of money. ill go get you the link
 
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