I did a search and only found one responce that said anything about dual 231s.

Has anyone done this? I have two sitting there getting dusty and 5.4 crawl is looking pretty nice. Especially if I can put the 4.0 in both. That would put me close to 160:1 crawl. Be nice if I only had to buy the extra low planitaries.

I know the issues with the 1" chain, but I am really easy on the skinny peddle.

Try lookinghere (http://bc4x4.com/tech/bryce/tcase/tcase.cfm)

Heres a little something I found a while ago.

http://www.bc4x4.com/tech/bryce/tcase/tcase.cfm

That'd sure put a lot of stress on that rear 231 planetary and shaft... Much better idea to use the larger planetary out of a 241 (like the guy in the article did) for the secondary gear reduction.

Thanks fellas. It was the same link but the info is great. I have my next rainy day project. :D

:nuke:
Thats all there is to be said about that. A 231 is hardly strong enough on its own much less with all the extra torque multiplication in front of one.

Have to admit it would add to the trail side entertainment though :D :nuke:

I'll throw a 4 to 1 and a nice SYE kit in the case and call it good.

why?
here is why:
the np231 can stand 1885 lb/ft.
if you'll use np231hd you'll get 1940 lb/ft
now - take your engine output*your 1st gear ratio*your t-converter*your first np231 (2.72) and you will see why wont it work.

lets go the other way around -
your second t-case will stand 1940 lb/ft - \2.72
your first t-case will have to stand 713 lb/ft - \2.72
your gear box will have to stand 262 lb/ft - \ 2.8 (i guess)
your t-converter will have to stand 93 is 2 lets say - \ 2
your engine output have to be (max) 46.5 lb/ft.

now would you like to go wheeling with that?????

laredo

Yeah, and with 130:1 gearing and a 200 horse engine, the axle shafts should (by the book) be 6 1/2" thick.

that said, why not go with one of the larger (ie stronger) planatary t-cases, this is going to require a tremendous amount of custom fabrication, wouldn't it be better to start with something you know is strong enough?

Chad



Originally posted by laredo
why?
here is why:
the np231 can stand 1885 lb/ft.
if you'll use np231hd you'll get 1940 lb/ft
now - take your engine output*your 1st gear ratio*your t-converter*your first np231 (2.72) and you will see why wont it work.

lets go the other way around -
your second t-case will stand 1940 lb/ft - \2.72
your first t-case will have to stand 713 lb/ft - \2.72
your gear box will have to stand 262 lb/ft - \ 2.8 (i guess)
your t-converter will have to stand 93 is 2 lets say - \ 2
your engine output have to be (max) 46.5 lb/ft.

now would you like to go wheeling with that?????

laredo

All good stuff.

I like having the option to go 2wd Low.

Why wouldn't I use a 241 like in the links. Well I have two 231 sitting there now.

I can cut, weld, machine all myself. (money invested so far: $0)

A SYE would almost certainly be tossed in here because it would be in a vehicle with 75" WB. ($300?)

the grade 8 threaded rod ($30)

The metal to do the shifting of the second t-case (I have those scraps).

Say, $300 for stuff that I am not thinking about now.

That means I have $630 into a dual case that will be going in my project crawler which is using a motorcycle engine and only weights about 1300. That includes the axles and tires/rims. So you see, laredo, you are exactly right. 46 ft-lbs would be the max and that is if the enigne was at full throttle. It will end up being a gloryfied ATV with a roll cage and really good wheel travel.

I have always leaned toward a light-weight crawler instead of power and weight.

You need to state that you are building a glorified ATV in your first post. That way it cuts down on the post about how its gonna nuke.

I say go for it if you are confident about making and adapter and spud shaft. I personally would not but I am not making a shopping cart with wheel travel either.

1) parasitic losses due to the 4 friggin billoin gears you have in your new drivetrain will be about 18%-ish.

2) I dont' care if you run a diesel in front of that drivetrain, it;s basically impossible to generate enough traction to use all that torque. you're in this to go slow, not turn the main turret on the USS New Jersey, so I really wouldn't worry about needing a 6" axleshaft.

Originally posted by Sundowner
1) parasitic losses due to the 4 friggin billoin gears you have in your new drivetrain will be about 18%-ish.


I think you are being really nice with that. I could easily be 25%+, but that doesn't really matter.

How are you hooking up the motor...You could get more reliable gear reduction with a chain, before the case.

Or another brain-fart. Run a 90 degree industrial gearbox between the engine, and case.... They can have up to 200:1 reduction alone......:D Hows that for a fawked up idea:flipoff2:

Yeah, what he said.

Seriously, on concrete your tires (off-road w/ big lugs) only allow 90% of the power to transfer through them. Way lower for dirt or anything soft.

So, if I had (we will use the whole weight of the vehicle) 1300 it would only allow (35" tires) 1755 ft-lbs of traction can be transmitted before the tire would spin on concrete. since you almost have to have two tires on the ground when applying the skinny peddle you would devide that in half.

Of course there will be spikes in torque but most of my wheeling is done at ideal or just off idle. I have an auto and have to ride the brakes most of the time. A better crawl would just help this out.

But it would be in a vehicle that would produce enough power to brake a chain much less a NP231. Well, not will that amount of reduction.

Lessee,

~3.2*200*2.7*3.07=~5300:1 (46 ft-lbs at that ratio= 240,000 ft of torque)

"Not going anywhere for a while."

"Grab a snickers"

Originally posted by Tim Smith
Lessee,

~3.2*200*2.7*3.07=~5300:1 (46 ft-lbs at that ratio= 240,000 ft of torque)

"Not going anywhere for a while."

"Grab a snickers"


They have 'em in different ratios.:flipoff2: :D :flipoff2:

thats plain stupid
if you are running 1300 lb car on 35' tires, you will have, at the ideal weight dist' 325lb per wheel (including un spurng weight)
traction means lb per sq/ft - your car will have no traction at all.
your best way to drive is to put the pedal to the metal....
then why would you need such gears?:confused:

am i right ? :flipoff2:

laredo:smokin:

Can always fill the tires with water for more weight at the wheels :flipoff2:

Originally posted by laredo
thats plain stupid
if you are running 1300 lb car on 35' tires, you will have, at the ideal weight dist' 325lb per wheel (including un spurng weight)
traction means lb per sq/ft - your car will have no traction at all.
your best way to drive is to put the pedal to the metal....
then why would you need such gears?:confused:

am i right ? :flipoff2:

laredo:smokin:

Ever rode on a 4wd ATV? I have never lacked for traction and it only weighs 600 max. And that is with a lot less tire (22") I have actually pulled an F150 from its roof to its wheels with just the ATV. Plus, with NO articulation in the back I have gone up 50* hills with rocks and through washes with ease.

I also think because the wheel base will be so short that 33" would be the most I need.

More tire than that and I would have to worry about visibility over the tire (bad j/k). :flipoff2:

Originally posted by LAME



They have 'em in different ratios.:flipoff2: :D :flipoff2:

Actually you have the same idea as me. The engine will either be over the t-cases or beside them. So I will have the option for that reduction too.

Yeah, I bet you can get them in 600:1 if you have the room. :flipoff2:

Originally posted by Tim Smith


Ever rode on a 4wd ATV? I have never lacked for traction and it only weighs 600 max. And that is with a lot less tire (22") I have actually pulled an F150 from its roof to its wheels with just the ATV. Plus, with NO articulation in the back I have gone up 50* hills with rocks and through washes with ease.

I also think because the wheel base will be so short that 33" would be the most I need.

More tire than that and I would have to worry about visibility over the tire (bad j/k). :flipoff2:

the thig with traction and ATV's is the fact that you can manipulate where the tractionand center of gravity is with your body.

Ever try to wiggle around in the cab of a truck to get that right front tire to grab alittle more:flipoff2:

Originally posted by Monkeyboy
Heres a little something I found a while ago.

http://www.bc4x4.com/tech/bryce/tcase/tcase.cfm

That's my article! :D

FYI, I've since sold the Jeep, but I never had any problems with the dual T-case other than the leaks.

--Rob

wouldnt it be waaaay easier to just throw a 4:1 kit in the 231 and put a marlin or klune-v crawler box inbetween the TC and Tranny?

Originally posted by evilpsych
wouldnt it be waaaay easier to just throw a 4:1 kit in the 231 and put a marlin or klune-v crawler box inbetween the TC and Tranny?

4:1 - not stock parts, so can't get replacements at a wrecker
- expensive
- no 2wd low range without spending more $ on a particular internal shift part
- didn't lengthen drivetrain like I wanted, to improve front driveshaft angles
KluneV - expensive
- didn't like the shifter mechanism
Marlin - not for Jeep T-cases (AFAIK - researched into that, Toyota used a version of the AX-15 but different tailhousing, and finding the correct one was hard and expensive)
Other dual T-cases (NP203, etc.) - too heavy, large, HD, hard to mate to the AX-15
Me - wanted to do it myself to save $ and learn in the process

--Rob

Originally posted by ryeguy


4:1 - not stock parts, so can't get replacements at a wrecker
- expensive
- no 2wd low range without spending more $ on a particular internal shift part
- didn't lengthen drivetrain like I wanted, to improve front driveshaft angles
KluneV - expensive
- didn't like the shifter mechanism
Marlin - not for Jeep T-cases (AFAIK - researched into that, Toyota used a version of the AX-15 but different tailhousing, and finding the correct one was hard and expensive)
Other dual T-cases (NP203, etc.) - too heavy, large, HD, hard to mate to the AX-15
Me - wanted to do it myself to save $ and learn in the process

--Rob

Pretty much the same thoughts I had. I looked over your article a while back and considered doing the same thing, I just ain't got the skills for something like that... For now I'm planning a Klune-V unless another viable option makes itself available for less $$... You didn't happen to make two of those creations did ya?? :D

Dave

If you're interested, I'll cost another out. It'd take some time to reproduce, though (I'd want to address the flaws in my original design, plus make it more generic).

--Rob

Originally posted by OverTech


Pretty much the same thoughts I had. I looked over your article a while back and considered doing the same thing, I just ain't got the skills for something like that... For now I'm planning a Klune-V unless another viable option makes itself available for less $$... You didn't happen to make two of those creations did ya?? :D

Dave

Originally posted by ryeguy
If you're interested, I'll cost another out. It'd take some time to reproduce, though (I'd want to address the flaws in my original design, plus make it more generic).

--Rob



Hell yeah I'd be interested! 'specially if it saved me some coin over going with the Klune... I want the flexibility to have an extreme crawl ratio without being stuck in extreme low everytime I shift to low range, ya know? I'm sure you do know, it's probably what drove you to build your own crawl box... ;)

Anyway, my current plan is to move my 4-banger forward about 6 inches to make room for a Klune. Then I was gonna swap out my 231's 21 spline input shaft for a 23 spline input shaft. The Klune would take a 21 spline input and have a 23 spline output.

A 4:1 Klune would put me at about a 194:1 in extreme low, which is more than I will probably ever need... So yeah man, if you can come up with another one of your custom creations that'd yield something around 130:1 as an option, I'd be very interested...

Dave

Okay, today is what, Tuesday? It's our long weekend, and the club's main 4x4 event (Rock Crawl 02, of which I'm on the committee for, so not much spare time right now). I'll try to get a # for you in a week. Email me directly a ryeguy@bc4x4.com if you don't hear from me.

To verify: 21 spline input, 23 spline output, length in 5.5-6 inch range, shifter lever, stock 2.72:1 NP231 (likely to get right input gear) or NP241 planetaries.

The kicker: I had all the parts for another, but gave the stuff away to the guy who bought the Comanche...

--Rob

Originally posted by OverTech
Hell yeah I'd be interested! [...]

Yup, that all looks about right to me... My direct e-mail is overtech@bellsouth.net and I'm usually around...

Originally posted by ryeguy
Okay, today is what, Tuesday? It's our long weekend, and the club's main 4x4 event (Rock Crawl 02, of which I'm on the committee for, so not much spare time right now). I'll try to get a # for you in a week. Email me directly a ryeguy@bc4x4.com if you don't hear from me.

To verify: 21 spline input, 23 spline output, length in 5.5-6 inch range, shifter lever, stock 2.72:1 NP231 (likely to get right input gear) or NP241 planetaries.

The kicker: I had all the parts for another, but gave the stuff away to the guy who bought the Comanche...

--Rob

If your gonna make one, ya can make two right? Id be interested. HMMMM, do I see the begining of a buisness here? Keep me in mind if your gonna fab up a crawlerbox or two.

Ken

Originally posted by kwrangln
[...] HMMMM, do I see the begining of a buisness here?

Hm. No, another product for an existing business. And I have no desire to push Lance's Pirate4x4 bounds (for commercial sales w/o paying for ad's). So if anyone is interested in one of these (or wants additional help doing their own after reading the BC4x4 article), then email me privately, either at ryeguy@bc4x4.com or rbryce@exaxt.ca. This is only for interest, for costing at this time.

Ken, Laredo, you're both on my list, I'll email you two when I email Overtech.

--Rob

Hey ryeguy, when you were building the crawler box, did it look possible to remove the ring gear for the planetaries from the bit of housing that was left. I've been contemplating doing something very very similar, but rather than use the steel ring, turn, mill and cut my own all aluminum housing for everything, to eliminate the sealing problems.

I'd be using the gears and such out of a 242 (that's what i have layin around) and probably mate it to a complete 241. don't really give a damn if i have to cut up the floor. New axles are going, and drivelines need to change anyway. Keepin 4:10's on the punkins (RC44 & 9") goin into what's left of an 89 cherokee.

my thoughts on this were to use the 241 as an intermediate case, toss the output housing and replace it with a machined spacer. Do Rob's TIG trick to get a workable output shaft that would feed into the 2nd t-case. I think this might cost another inch or two in driveline length, but it should be monkey-simple.
now, what would be REALLY fun is if the 241 Driverside front output could be extended out the back of the case by the same method used to modify the output shaft. then you'd have a nice rear PTO with more sppeds than my bicycle.

Originally posted by 1337j33px0r
Hey ryeguy, when you were building the crawler box, did it look possible to remove the ring gear for the planetaries from the bit of housing that was left. I've been contemplating doing something very very similar, but rather than use the steel ring, turn, mill and cut my own all aluminum housing for everything, to eliminate the sealing problems.

I'd be using the gears and such out of a 242 (that's what i have layin around) and probably mate it to a complete 241. don't really give a damn if i have to cut up the floor. New axles are going, and drivelines need to change anyway. Keepin 4:10's on the punkins (RC44 & 9") goin into what's left of an 89 cherokee.

The design I'm working on right now would replace the entire stock housing. Yes, you can remove that ring gear. You have to heat up the aluminum to expand it, though (at least, that's what we did).

Watch out for the NP242. It's unique that the input gear is a different length than the other NP231/NP241/etc. cases. Not sure why they did it, but it won't interchange with other cases. Tried to assemble a NP231 with a NP242 input gear once...that how I found that out.

--Rob

Add me to the list of people you email would you Rob? RatherBeJeeping@hotmail.com

Originally posted by ryeguy


The design I'm working on right now would replace the entire stock housing. Yes, you can remove that ring gear. You have to heat up the aluminum to expand it, though (at least, that's what we did).

Watch out for the NP242. It's unique that the input gear is a different length than the other NP231/NP241/etc. cases. Not sure why they did it, but it won't interchange with other cases. Tried to assemble a NP231 with a NP242 input gear once...that how I found that out.

--Rob

Well, i'm using all 242 parts for the box, so it shouldn't be a problem. Do you think the extra modes in that TC will pose a problem as far as reusing some of the linkage. I've grown to hate that fulltime shit (that center differential creates a ton of slop in the driveline, even when locked.)

Would i have any problems mating the 242's output shaft to the 241's input gear? they aren't 32 spline are they? I know it's beefier. but that's about it.

Thanks for all the info too, really helpful. i owe ya one. :beer:

Originally posted by 1337j33px0r

Do you think the extra modes in that TC will pose a problem as far as reusing some of the linkage?


No, I can't think of any problems.

Originally posted by 1337j33px0r

Would i have any problems mating the 242's output shaft to the 241's input gear? they aren't 32 spline are they? I know it's beefier. but that's about it.


Whether it's a NP231, NP241, or NP242 shaft that engages the low range planetaries' shifter collar, it will need resplined or tig welded to the following T-case's input gear.

--Rob