:flipoff2:

well after reading this thread:
http://www.pirate4x4.com/forum/showthread.php?s=&threadid=56045&perpage=25&pagenumber=1

i was inspired

after speaking to a few transmission companies i was let down and feeling quite dismayed, it was impossible to join the two, i tried to look at it myself but only succeeded in pulling the gearbox apart and getting very confused
:D :(

well i had the two H41s sitting there for a long time, and with the 42s on the way :flipoff2: i decided it was time to get lower gears, and after exhausting all the options, kluneV, marlin crawler, dual mini cases ;), marks adapters gearsets and even contemplating waiting until the end of the year for the cruiser crawler, no joy... mostly i didnt want to part with the $$$ for the gears, i looked at 6.17 r&pinions, more sotries and pictures to come on that soon!! ;) got the pair for $100, but they are coarse spline and notoriously have strength issues

as a passing joke, and just trying to get a bite, i told one of my mates greg (1madengineer) he got a wood, and i took the H41 over to his work at midnight last night, and after knocking off some fittings and checking my bearings in the new hydro steering box, we took a look at the gearbox, and started drawing up measurements and ideas

project: ITS AWWWN BABY
is in full swing, i should have gethered most of the parts by the end of the week, and it will add 16" to the drivetrain, the new setup will read like this:
4.89 gearbox, 4.89 gearbox, 2.28 transfer case, 4.11 diffs,
this comes to around 224.07 or something similar who cares, its plenty for me at the moment, and with transfer case gearsets, it can be easily made over 300:1, but that would cost more money

sorry, that im ranting so much, but im pretty excited...

btw: does anybody have any CAD drawings, they can email to me or links to some on the net

im specifically after drawings of 19tooth 35mm H4speed gearboxes, any details, pics or tech info, i run a split case behind it all, this is the shaft that exits the gearbox and goes into the transfer, but any spec charts on split case, or H4 boxes would be awesome

cheers guys
ill keep youse updated with pics and specs when the new parts get here.......i'll even tell you all how to do it...but you need wheelbase :p

according to the calculator on Marlins website...I come up with a much better crawl ratio than 224 to 1...I could be wrong...math never was my strong point...course, all I did was plug in the numbers.

H41-Non-US X Gearbox #1 X Gearbox #2 X T-Case X Ring&Pinion

4.93 X 4.89 X 4.89 X 2.28 x 4.11=1103.58 to 1...........Yikes...now thats crawlin baby!:D

You may have a better setup than you initially thought!

the calculations you mention reflect 1 gearbox and 1 t-case...add the second gearbox like you plan and you will be crawlin.

4.93 X 4.89 X 2.28 X 4.11=226 to 1

Good luck mate!

DUDE

im not gunna be THAT long, you got three gearboxes in your mix, i only want two, and i dont want to go more than 110-112" in the wheelbase

gearbox#1, gearbox#2, transfer case (stock split case) diffs, (stock ratio) until i can get some BUILT 60s or similar :D

now you have me confused

here is what i am doing

gearbox, gearbox, transfer, diffs

BUT

i will get pics later in the week......when i go back up to view the progress :D

the first figure is not a gearbox...it is the 1st gear ratio of your H41...add up the numbers...i'm pretty sure I'm right!

Peace out!

How to determine crawl ratios! (http://www.marlincrawler.com/dual_mc07_intro.html)

Check out the link mate!

Your eyes shall be opened.:D

For example....here is your current crawl ratio....

H41 non-US 1st Gear=4.93
Split Case=2.28
Ring & Pinion=4.11

this adds up to 46 to 1

Here is mine...by the way, it really sucks....

J30 3spd 1st gear=2.75
3spd t-case=2.31
Ring & Pinion=4.11

this adds up to 26 to 1

Is this making sense yet?

Originally posted by BJ On Roids
:flipoff2:

well i had the two H41s sitting there for a long time, and with the 42s on the way :flipoff2:
setup will read like this:
4.89 gearbox, 4.89 gearbox, 2.28 transfer case, 4.11 diffs,
this comes to around 224.07 or something similar who cares, its



I get it! Are you saying that you are going to put 2 4speeds together? Now that would be an engineering feat...let us know how it turns out...at least we all know how to figure out our final crawl ratios! LOL!:D :D

Originally posted by BigDave
For example....here is your current crawl ratio....

H41 non-US 1st Gear=4.93
Split Case=2.28
Ring & Pinion=4.11

this adds up to 46 to 1

Here is mine...by the way, it really sucks....

J30 3spd 1st gear=2.75
3spd t-case=2.31
Ring & Pinion=4.11

this adds up to 26 to 1

Is this making sense yet?

that sux...ill bet you need heaps of horsepower to move it along!!

NOW

ill bet im right dave-o....old mate...ive had another moment,

nonUS H41
nonUS H41
split case
diffs

thats all im doing, nothing more
just that!!
so your second calcs are right and my original ones

know of any cad drawings and stuff out there for thses things?
bellhousing,
transfer case
input, and output shafts?

out of curiosity, have you calculated the gearing with both gearboxes in reverse?
the reverse gears are often lower than firsts,(dunno about those trannies you're using tho)
and double reverse equals forward....

yeah, i think reverse is either equal to first or reverse may be:
3.555, but either way its plenty, double reverse = forward, and yeah lots of cool things, including a third shifter to put a stubby cooler on :flipoff2:

bigdave the 42s (were tyres):D

GUYS:
i need some specs

CMAWWN
cad drawings, or spec sheets or something

There was a thread on double SM465's on the General Board last year. I think that is the way to go if you can eek out enough wheelbase to get it all together.

Good luck!

Originally posted by BJ On Roids


that sux...ill bet you need heaps of horsepower to move it along!!



My boat anchor F motor snapped the rear driveshaft right in half on Fordyce 2 weeks ago cause I had to go too fast...already started the engine and tranny swap...4.3 V6 TBI with 700R4 and 205...no more clutch for me...no more flying over obsticles...:D

I've been wanting to put two LC 4-speeds together for a while. Remember to only shift the front one and use the second one like a t-case, or your syncros will begin to dislike you. Make an extra adapter for me would ya? :D

Originally posted by wngrog
There was a thread on double SM465's on the General Board last year. I think that is the way to go if you can eek out enough wheelbase to get it all together.

Good luck!

thats the link i posted in my first post:D the wheelbase will be the limiting factor

im going to need to be around 110" to get a stock length rear shaft, but on the plus side, NO overhang

Originally posted by wngrog
There was a thread on double SM465's on the General Board last year. I think that is the way to go if you can eek out enough wheelbase to get it all together.

Good luck!

I remember that thread, there is a guy here in Utah that mates 465s...I think it was Gaylon Pugh Driveline service in Lehi, Utah.

I saw one for sale at Six States in SLC and they were one low geared mutha.

bennett

COOL!!
Finally getting lower gearing huh..

Chris from OTT industries mated a T18 to a SM465 in a similar fashion. Perhaps he could give you some pointers!


:)

Ok, I will bite and play the role of devil's advocate. I don't want to sound critical -- just throw out some additional points to consider.

I am aware of several projects where two trannys have been mated. IIRC in all cases the second has been an SM465. I think that is important becasue the second transmission's input shaft will recieve up to 4-5 times the torque for which it was originally designed. The second input shaft, together with the synchro gears in the second tranny will be the weak links. The SM465 is unquestionably stronger than the H41, so I would worry about the strength of the rear H41 input shaft.

The cheapest way to mate the two is with a plate adapter and a splined female collar connecting the rear output shaft of the front tranny with the input shaft of the rear tranny. You will have to shorten and re-spline the input shaft of the rear tranny. One reason SM465s have been used is that both input and output shafts are 10-spline, thus making the collar a simple slip on unit. You will either be challenged with mating 10- and a 19-spline shafts or having a 19-spline input shaft made for the second transmission.

Finally, I have to ask if you think the Toyota split transfer case, even though stronger than the older units, will hold up to increasing the input torque by almost a factor of five?

I would think very carefully about all of the pros and cons before embarking on this kind of project. You also need to think about whether or not you REALLY need 240:1 gears as opposed to something in the 100-150 range?

Originally posted by Medusa
Ok, I will bite and play the role of devil's advocate. I don't want to sound critical -- just throw out some additional points to consider.

I am aware of several projects where two trannys have been mated. IIRC in all cases the second has been an SM465. I think that is important becasue the second transmission's input shaft will recieve up to 4-5 times the torque for which it was originally designed. The second input shaft, together with the synchro gears in the second tranny will be the weak links. The SM465 is unquestionably stronger than the H41, so I would worry about the strength of the rear H41 input shaft.

The cheapest way to mate the two is with a plate adapter and a splined female collar connecting the rear output shaft of the front tranny with the input shaft of the rear tranny. You will have to shorten and re-spline the input shaft of the rear tranny. One reason SM465s have been used is that both input and output shafts are 10-spline, thus making the collar a simple slip on unit. You will either be challenged with mating 10- and a 19-spline shafts or having a 19-spline input shaft made for the second transmission.

Finally, I have to ask if you think the Toyota split transfer case, even though stronger than the older units, will hold up to increasing the input torque by almost a factor of five?

I would think very carefully about all of the pros and cons before embarking on this kind of project. You also need to think about whether or not you REALLY need 240:1 gears as opposed to something in the 100-150 range?

torque?
yeah an awful lot, i'll bet it breaks things....to me wheeling is half fixing, i wish i could buy or build something within my budget that never broke and drove everything i pointed it at and then turn around, drive it home and drive it to work the next day..but to me, at the moment its not possible

i can get 100-150:1, but not over here, for the money i can afford, :( if i had the $$ then no worries, but its going to cost me $2000 just to get it to 90:1 and ill still be running cruiser diffs and driveline :( i have been tossing gearing options around for an awful long time, and i have pages of notes written down, and have received lots of info from guys on this board (thanks guys)

keep in mind it won't always be at 220, i can make it as low as 35:1 in low range and just leave the front box in 4th (1:1) thereby not adding any additional torque to the rear box for street driving, and preserving the life of the box/synchros and input shaft, offroad, i wont need to shift quickly, or anything and should be able to take it easy on the box making it last a little longer, also the shifting i plan to do will all be done in the rear box, and leave the front in a set gear, i.e medium speed trail may select first or second in the front box and shift in the rear box, and i did think about this, for quite some time...

i hope you dont think i just jumped on and said yeah, lets do it!!

the H41 is a pretty strong box, yeah, first job (which we are doing right now) is making the front output 19spline, we got another rear output and are using that, making it the front output (you understand??) then a 19spline 35mm collar will sleeve the two, finally an adapter plate and oil circulator will be added.. then it will be ready

if its all a failure, which it won't be it should hold up for a while...then it won't have cost me that much

and finally i dont care what you say...im doing it anyway....:D so it sounds stupid to you:confused: oh well...im stupid:D and SLOOOW too........

ohhh..the split case...yeah..to be honest with you, i was worried about that myself :( in fact i predict instead of the input shaft on the second gearbox, as you suggested, i beleive the output shaft on the rear box, or something in the split case will definitely go BOOM before the gearboxes. i'll be breaking my cruiser axles and pinions too though! so remember, there is some nice weak 1.31" 30 spline fuses down back!!

but you guys now have this option
sm465, or sm420, followed by minitruck case, in some cases with 4.87 gears in it, followed by an older landcruiser transfer case...marlin crawler sells these (i beleive or similar setups that can run you 150:1 or more)

this would also exponentially increase the load on that poor weak unit :nuke: mine should be as strong as this setup, (i think, and hope maybe stronger) also i have heard of people putting an NP205, in the mix also, i am curious to know if you think these guys are in the same boat as me (i.e. risk of destroying driveline?) or if they are going to have stronger setups, if you beleive there setups are going to be stronger and more reliable...why do you think that? apart from the fact they are ONLY 150:1 (which is still an awful lot more than the cruiser case can handle) cheers
thanks for the props!!

and when it goes :nuke: you can tell me you told me so!!

i saw a guy with a auto and 10:1 reduction box, break the input shaft on his NP205, and it was heaps beefy, just twisted and sheared it off......

hes running a 454, and 44" boggers though....

I didn't say that it was a stupid idea -- I was simply pointing out some concerns about this general approach. If this is something you really want to do, then go for it.

also the shifting i plan to do will all be done in the rear box, and leave the front in a set gear, i.e medium speed trail may select first or second in the front box and shift in the rear box, and i did think about this, for quite some time...

I think you will find that it will be very difficult to shift the rear transmission while moving. The added angular momentum of the gears moving in the first box (regardless of what gear it is in)will be too much for the synchros of the rear box to handle. I could be wrong, but I predict that the second tranny will be extremely difficult to shift (especially to downshift).

If the first transmission is in 4th or 1:1 what would it matter to the second transmission. As far as it is concerned it has a real long input shaft. As far as putting extra torque on syncros etc. in the second transmission. ......there may be issues there.

Having driven at 300:1 I will tell you the first time I drove it, I thought the darn axles were going to walk out from under it!!

It all depends on the nut behind the wheel and how happy he/she gets with the go pedal. I know I could drive up a wall and not break. I could also do the same thing and be sure to break something.

having 2 H41/H42 sounds real cool. I would need a spreadsheet to figure out what freakin gear I was in though..............wait I already need one.......with SM420 and 4.11
dual_____4.7:1 only___stock2.31
314:1____136:1_______67:1
159:1____69:1________34:1
76:1_____33:1 _______16:1
44:1 ____19:1________9.5:1

thanks old rock doc...

i do value your opinion and experience and thanks for the information, i will be sure to post pics and info on here about what its like....... im still super excited :D

but im sure i will figure it out....very soon it will be a trail only rig anyhow, so shifting, shouldnt really become a problem

cruzilla, what axles are you running and what tyres?

If the first transmission is in 4th or 1:1 what would it matter to the second transmission. As far as it is concerned it has a real long input shaft. As far as putting extra torque on syncros etc. in the second transmission

If the front transmission is in 4th gear there is no additional torque supplied to the rear transmission, so you are correct, Cruzila, in terms of torque. However, my last post had NOTHING to do with torque, but rather with the angular momentum directed to the rear transmission. To shift from one gear to another, the synchro gears have to either increase or decrease the speed of the shaft on one side or the other of the shift configuration. In order to change the speed of a gear shaft, you need to overcome the angular momentum of that shaft -- this is the job assigned to the syncho gears. Angular momentum (mvr) is substantially increased through a transmission, even if the tranny is in a 1:1 gear ratio. It is increased by the sum of the mass of each gear turning in the first transmission multiplied by the radius of each gear turning in the first transmission and then by the revolutions of the turning gears. So, in terms of angular momentum, the first transmission is most definitely not just a long input shaft.

I have both direct and second-hand experience with the difficulty of shifting a transmission when additional gears are placed between the flywheel and a transmission. Believe me, you should be aware of the consequences of this principle of physics.
BJ on Roids... I admire both your experience/knowledge and your willingness to try new modifications. I hope it works for you, and I trust that you will let us all know how this conversion comes together. Don't worry that any experiment might not quite meet your expectations. Our knowledge is increased by both successful and unsuccessful modifications, and I bet I lead the Cruiser community in unsuccessful ideas.:D

With all the excitement BJ didnt remember what we talked about(it was 12.30 in the morning), the front box will remain as standard shifting duties, the 2nd box will act basically as a 4sp "klune" (selected only when stationary) leaving the tcase for 4wd splitting duties. The input shaft on the 2nd box will be changed to equal to output shaft size allowing a single splined coupling to be used (luckily input & output bearing sizes are the same).

Medusa, got it. Sounds like a grinder :eek: i was kind of looking at your devils advocate post. I guess I got it mixed up anyway.

BJ, I am running 37" MTR's, stock axles, stock birfields, fine spline 4:11 and a Custom FF in the Rear. I am having problems with the aisin hubs in the rear. The innards are cracking. The last set exploded interally. I was having this issue before the dual case though.

Hey with both in 1st gear and 4:11 diffs it is 100:1 who needs a low range in the t-case?

Cheers

I think you said that your turbo 2H put out 750nm, and thats only 3 times the standard torque on the first input shaft, 15 times the standard torque on the second input shaft and then only 70 times the standard torque in to the transfercase.

Originally posted by cruzila
Medusa, got it. Sounds like a grinder :eek: i was kind of looking at your devils advocate post. I guess I got it mixed up anyway.

BJ, I am running 37" MTR's, stock axles, stock birfields, fine spline 4:11 and a Custom FF in the Rear. I am having problems with the aisin hubs in the rear. The innards are cracking. The last set exploded interally. I was having this issue before the dual case though.

Hey with both in 1st gear and 4:11 diffs it is 100:1 who needs a low range in the t-case?

Cheers

OUCH, but im running 38s at the moment and plan to run 42s, on this setup!! :NUKE: :NUKE: how on earth did you get 314:1 and was it expensive!! tell em your setup

sounds like a wicked crawl ratio!!

with your aisin hubs exploding, ive only had that happen once, due mainly to a birf piece getting lodged in there and further destroying itself..

have you thought of running just straight out drive flanges or plates, like from the front of a FZJ80 front diff...if they are splined the same??.....wouldnt stick out as far, and no chance of failure.....

although those aisin hubs are pretty STOUT little units!!

Originally posted by jbt
I think you said that your turbo 2H put out 750nm, and thats only 3 times the standard torque on the first input shaft, 15 times the standard torque on the second input shaft and then only 70 times the standard torque in to the transfercase.

70 times what it was supposed to run..and in harder conditions :nuke:

:D :flipoff2: :p but DAMN it'll be going slow when it happens

projectile carnage is a cool thing (as long as nobody is hurt):p

:flipoff2: yeah i dredged this beast up too!!
we have gotten the gearbox apart, and on the 19tooth H4x, gearboxes, the input and output bearings are the same, we were using a puller to get the bearings out and snapped the teeth off it!

SOOOOO
we have one bearing to go, the front output, will now cut down and the first gear inside that will be machined out to the exact spline count as the output shaft, then on the front gearbox, the output shaft will be cut right down, and we will get around 42mm of toothe contact (the same amount as on the first gear that the part reaches in the split transfer case) or within a hair of that anyways! the adpater plate, will share oil between both boxes and we should be away....

BJ, Your a crazy Mutha!!!:beer: :beer: :beer:

Originally posted by sixty
BJ, Your a crazy Mutha!!!:beer: :beer: :beer:

HEHEHE, well, i cant drive to save my life, so i make up for it, by building a better rig, and having no driver ability!!


PICS SOON :D