Topic: INFO FROM BUDBUILT!

[Marketing]

Sweet looking bed!

[csudman]

Why, thank you.

[csudman]

Little Progress

[FATB0Y]

Little Progress

I here ya

[BigMike]

Any updates on this? Finished pictures? How has it been holding up?

[hudlenutz]

BigMike

not to split hairs, or trannys for that matter, but 50 transmissions @ 3.95 (1st gear) would be 675856945666696925678609361162:1.  Not 197.5:1.  The gear ratios multiply.  Consider a tripple case with stock gears  that's 2.28*2.28*2.28, not 2.28*3, so 50 trannys would be 3.95^50. 

I'd like to have the overdrive option of the dual tranny setup.  Imagine gearing your truck for the trail, then driving the highway with the rear box in 5th.  That'd be sweet.

If UNBREAKABLE is around, we should see how his dual tranny monster is holding up...
http://board.marlincrawler.com/index.php?topic=13590.0

[BigMike]

BigMike

not to split hairs, or trannys for that matter, but 50 transmissions @ 3.95 (1st gear) would be 675856945666696925678609361162:1. Not 197.5:1. The gear ratios multiply. Consider a tripple case with stock gears that's 2.28*2.28*2.28, not 2.28*3, so 50 trannys would be 3.95^50.

oh yup, you Sir are correct I figured my mind would go sideways after writing that anyhow haha Dang, then that is even more to my point, that there is no way in hell that a Transmission can hold up to the torque of "stacking them".

I'd like to have the overdrive option of the dual tranny setup. Imagine gearing your truck for the trail, then driving the highway with the rear box in 5th. That'd be sweet.

That would be pretty sweet, that would turn 5.29s into 4.50s for the Highway.. But could you imagine driving your truck everywhere with the power going through 5th gear all the time?? yikes

[blackdiamond]

Hey csudman,

I was thinking about the torque loads on the trans and then I saw it mentioned on the pirates as well so I thought I would bring it up.

22R-E: 3.95 x 112 hp & 142 tq = 442 HP & 561 TQ
22R: 3.93 x 96 hp & 129 tq = 377 HP & 507 TQ

I really dont think I would run a L- or G- or W-series trans behind a 500 ft-lb V8 engine!!!!!!!!

Im really courious to see how the trans hold up. Please keep us updated!!!

I realize that this is an old post to quote, but it is related to a later post that was impressive.  BigMike has an engineering mind!  Don't change your major!

I was thinking that as long as the first transmission was run in 1:1 on the street (maybe a pain to shift the rear transmission?) the 2nd transmission should be fine.

Using your logic, 22R: 3.93 x 2.28 x 96 hp & 129 tq = 860 HP & 1156 TQ to the 2nd transfer case.  I wouldn't run a stock toyota transfer case behind an 860 hp engine, but...isn't the reason they survive because they don't have impact loads at crawl speeds?

Wouldn't this apply to transmissions as well?

[blackdiamond]

Futhuremore, Marlin's tripple Crawler with two sets of 4.70:1 yields a 198.9:1 ratio in front of the output shaft in his transfercase, and he's had this installed and operating since '97 I believe and he has yet to break an output shaft. At this rating, if his engine is putting out even 120 ft lbs of torque, then that's no-joke 23,873 ft-lbs of torque entering his output shaft.

I have been thinking about this today and I think that I had a moment of clarity and I'm going to raise the BS flag.  Keep in mind that BigMike is extremely smart and I respect his knowledge, plus he may explain why I am a  for what I am about to post.

Exibit A: Marlins truck with the following gearing - 3.93 1st gear in transmission, 2.28 low in t-case #1, 4.70 low in t-case #2, 4.70 low in t-case #3 & 5.29 (just a guess) ring and pinion.

Exibit B: According to Bobby Long, the 30-spline 4340 chromoly inner axle on the short side breaks around 9,000 ft-lb, and I think that this is the strongest axle on the market.  He showed me a broken axle yesterday when I picked up my superset.

If BigMike is saying that the output shaft on Marlin's rear transfer case is getting 23,873 ft-lb of torque, then I have to assume that the axles are getting that much multiplied by 5.29 or whatever the ring gears ratio is and THIS IS NOT POSSIBLE!

It seems that mathmatically the torque he is quoting is available, but the drivetrain only sees the minimum amount of torque required to either move the truck or break traction.  If the tires/wheels were held stationary, there is plenty of torque to destroy all four axles or whatever the weak link is.

Does this make any sense to anyone else?

[BigMike]

Dang, I had written a nice reply and then I closed the window while cycling between my calculator and firefox..

I wrote a lot, I will just write what my point was. I cant remember everything......... man I hate this



Ok, trying to make since out of this, I know that a 3RZ is rated at 150 hp stock at the flywheel. But when I read the post about the Turbo 3RZ guy from Aus(?), he says that with his 3RZ stock, it was putting out about 85hp to the ground. So that is a 56% difference. What? Are we to assume that there is really a 56% power loss through the drivetrain of a truck? I have always believed that with a transaxle, there is about a 20-25% power loss, and with a transmission/driveline/diff, it is more like a 25-30% loss. Can the addition of a t/case really make it almost a 60% power loss??

Now I have always wanted to dyno my truck to see how much power it is really putting to the ground, but it seems silly to rate a vehicle's power in this manner. Because what if I put 40" tires on my truck, would I only see 50 hp to the ground? And then what if I put on 31" tires, would I see 100 hp to the ground? Now I dont work at a dyno shop, so I dont know this, but even if they were to take off a tire, precisely measure its dia, find out the ballooning effect (change in dia under rpm), and then weigh the tire, they use the ASE corrections (or whatever it is) where they try to use a formula to correct the power loss through the drivetrain, and then use that to multiply the ground hp to "estimate" the hp at the crank.

But who is to say what gear ratio works best for my engine? How can they know that formula? Maybe my truck would put more power out with 4.88s + 35" tires instead of 5.29s + 35" tires. How would anyone know that? So I am just supposed to dyno my truck and then that would be a ratio that would only apply to my situation with my setup? Of course this is true, but in Fresno, we have what they call a "Chassis Dyno" where they take off the wheels/tires and attach the dyno directly to the spindle. This is of course more accurate, but again, my axle gearing can affect the power transfer to the axles even...

So with that said, I have always been curious about the power lost through the drivetrain of our trucks.

Now lets play with some numbers, using the same direct-torque-multiplication I used.. Our dualcase adapter's double roller bearing is rated at 14,600 ft-lbs. With my setup, by the time the power is getting to my 2nd adapter plate, I've got 177 ft-lbs from the engine > x 3.95 trans > x 2.28 1st Crawler > x 2.28 2nd Crawler = 3,634 ft-lbs acting on that bearing, which is rated at 14.6k, so that is ok..

Marlin's setup, 177 ft-lbs engine > x 2.28 1st Crawler > x 4.7 2nd Crawler = 7,492 which is still within limits.

But then we take his 3rd T/case that has another 4.7 gear set, and now we have 35,213 ft-lbs leaving the transfercase.
Then take his 5.29 diff, and we get 186,276 ft-lbs, and since the differential splits the power, so will I, so divide that by 2, and we get 93,138 ft-lbs on each rear axle.

So clearly, this is far to much if Bobby Long has his axles rated at 9,000 ft-lbs.
So, just for fun, let's calculate a power loss ratio that will spare a rear axle life. From what I know, Marlin has never broke even a stock rear axle in his truck. So I am sure he is putting even less than 7,000? through each stock axle, if not less, but, that was also with his old engine. Right now, after the 3RZ conversion, we also decided to upgrade his rear axles. So lets just assume he is around 8,000 ft-lbs torque to the rear axle. BTW, This is where this calculation will be in error because I really have NO IDEA how much torque his axles can even sustain, or even what percent of that they are receiving.
But for the sake of the argument, lets just assume he has 8,000 at each axle.

So, if the direct multiplication shows 93,138 ft-lbs to each axle, and we only want 8,000 ft-lbs, then the power loss is calculated to be 86% by the time it gets to each axle shaft.

Wow.

Of course this HAS to be true because a gear ratio IS A TORQUE MULTIPLIER. So with all of the friction and gear movement, gear shafts being forced into pocket bearings, and forced into shims, and everything, there is enough friction there for at least an 80% power loss through the entire drivetrain of a transmission > three crawl boxes > transfercase gearing > driveline (including weight and change in angle from cv joints) > differential.

Ok, so now I wonder what the failure rate is of a stock transfercase output shaft. Then we can eliminate the power loss through the driveline and rear diff, and be more precise with this by only determining the power loss through the transmission and transfercases.

But I am happy to see this. Geez, least we not forget, this is the power allllllll the way down the line. I am willing to bet that the majority of this power loss is coming from #1 the driveline, #2 the rear diff, and #3 the transfercases.

With that said, I bet the power loss from ONLY the transmission has gotta be much less then 20%.
Therefore, if you start stacking transmissions, there will still be some good power entering into each one. Granted it is not being multiplied by much (only a max of 3.95 in this case), but if you take 144 ft-lbs torque from a 22R-E > x 3.95 1st transmission = 568 ft-lbs.

So now, even if assume a 20% power loss from the 1st transmission, which is highly favoring this setup, then you've got 454 ft-lbs entering the 2nd transmission.

Let me say that again, you've got 454 ft-lbs entering the 2nd transmission. This is the best-case scenario for the transmission. what if its only a 10% power loss? Then you are looking at 511 ft-lbs entering the 2nd tranny.

Seriously, I would never ever in my life want to run a W56 or a G54 directly behind a 450 ft-lb to Engine.

Think about it, a brand new 2006 Corvette ZO6 with a 452ci (5.7l) V8 is rated at 450 ft-lbs torque.

So lets have a vote, who where would want to go racing with a 5.7l Z06 Corvette V8 Engine while using a G54 transmission?

Yes, it is obvious that I am against this. Maybe I am crazy for thinking this way. It has nothing to do with any influence from Marlin or Marlin Crawler, or the fact that we are loosing customers to the dual-transmission craze. Do it, I want to see more of these. But it's just my opinion that a G54 can not last very long in a Z06 Corvette. I must be crazy.

Mike

[FATB0Y]

Mike are you outta breath?


J/K 

[BigMike]

WOAH WOAH WOAH

This is Crazy.


No, I am still thinking about this, and there is no way that there is an 80+% power loss. I Guarentee there is a potiential for more than 9,000 ft-lbs to pass through each rear axle.

Look, I am talking about 177 ft-lbs tq, right? Well that is the peak power, what, 4000 rpm for the 3RZ?
And 9,000 ft-lbs is the breaking force.

Now imagine if you had a tripple Crawler (1,024:1 final drive) and you put it in first gear and revved it to 4000 rpm, and then somehow completely held on to the rear axle shaft.

That doesnt happen in real life. For those skeptical of this, you have never seen Marlin's truck wheel at 1,047:1. He would have to have like 50" tires with dual bead locks aired down to 1 psi and then wedged up against an undercut rock with his truck fully loaded with a bunch of toyota parts or something... I can not imagine this scenario by myself. I have NEVER seen ANYTHING even alter his idle rpm while engaged at 1,047:1. HIS IDLE RPM. What is that in terms of torque? Like 10 ft-lbs of torque at 750 rpm? Imagine 17.7 times that power in the same situation. No way, I can not imagine this.

I have no doubt that at 1,047:1 Marlin's truck is putting much over 9,000 ft-lbs to each axle when revved up to 4000 rpm. I am willing to bet there could be 10k, 20k, 30k, 40k, 50k+ ft-lbs of torque there, if nothing else were to fail.

So now we need to think about there the weakest link is. If he had brakes from a Big Rig truck, and you used a sumo wrestler to press down on the brake pedal, and then you let the clutch out in 1st gear tripple low and then rev the engine to 4000rpm, I promise you, that if the brakes hold, you will blow the crap out of something from the drivetrain. Engine mounts? Trans? Crawler Coupler? Input gear somewhere? T/case output shaft? Twist the driveline? Blow the ring'n'pinion? Or of course, twist a rear axle shaft? Split the rear axle housing? Tear the brakes off of the axle housing?


wow... seriously

[FATB0Y]

You have entirely too much time on your hands.

[blackdiamond]

BigMike,

I think you are missing one tiny point...

An engine may have the potential for say 100 ft-lb of torque output, but unless the transmission requires that full amount of torque to turn, then the all of the torque is NOT transferred into the transmission.  The torque is ONLY transferred under load.  For example, it takes more torque to maintain a given speed going up hill, but the same rpm can be maintained on the flat (cruise control) which would required less torque to maintain the same speed, BUT the engine potential is the same.

[BigMike]

That is a good point bd

But I guess what I am saying is that if you were in a binding situation, then the demand for more torque to unbind the tires would increase, and inventually the peak power would be developed by the engine if the situation was maintained for a long enough period.

Which then brings us back to your previous point about crawling. Crawling is cake. Its like riding on a downhill slope on a mountain bike in 1st gear. You don't need much torque at all to propel the bike forward. Same with 108:1 or 223:1 or whatever. The torque requirement from the engine is reduced in order to propel the truck forward.

But of course things do not break when there is no load on them.. at least they aren't designed to When I think about a birfeld breaking, I quickly think about a truck pointed downhill with the wheels turned and then the driver gives throttle in reverse. There is a large demand for an increase in torque in order to rotate each front tire in reverse, so the engine meets that demand by increasing each injectors dwell time and retarding the timing, etc.

Nonetheless, You have a GREAT point that there is not as much torque as I am saying there is. In normal situations, there is not. Only under high/fully loaded situations.

I really love chatting about this bd. Seriously, I am only here to gain knowledge and learn from mistakes/experiences. If I am a guru or seem to know anything about what I am talking about, then it is just in my small little world that I live it. And believe me, I live in a pretty small world, just ask my girlfriend, she tells me that all the time

BigMike

[FATB0Y]

Ya just had to get him started again

[blackdiamond]

Now it's my turn to post twice 

I am going to hold the line and say that no part of the drivetrain will ever see more than 10,000 ft-lb of torque.

Marlins truck would only require 8.6 lb-ft of torque from the motor to break the Bobby Long axle at 9,000 ft-lb capacity.

9000 / (3.93 x 2.28 x 4.7 x 4.7 x 5.29) = 8.6   Note: I am assuming that if one wheel is off the ground the torque doesn't split at the differential.

This would mean that at 6000 rpm the motor would only have 9.82 hp.   HP = Torque x RPM / 5252

I suspect that 9000 ft-lb would shear bead locks and turn wheels inside the tires.

If the transfer cases were all in 1:1 then the torque in the transmission could be higher, but not more than 1701 ft-lb when the axle breaks and would take 433 ft-lb of torque from the motor.

9000 / 5.29 = 1701 ft-lb  & 9000 / (5.29 x 3.93) = 433 ft-lb

[blackdiamond]

BigMike -

Does this look familiar?

Comparisons:

               Inchworm's Mainshaft bearing:               Marlin Crawler's Mainshaft bearing:

Ball Count:                8                                       32
Static Load Rating:     5,850 lbs                            11,600 lbs
Dynamic Load Rating: 11,400 lbs                           14,600 lbs
Bearing Width:          23mm                                 30mm
Largest Spline Size:    21-spline Only                       21- or 23-spline available
Heat Treated:           No                                      Yes

Do you or any of your mechanical buddies know how to calculate the required torque for the dynamic and static loads?

I am a civil type so I'm not sure.

[BigMike]

I have a friend who just took Dynamics last semester, and I am taking it this upcoming semster. I could ask him about it, or I'll just look it up in the book once I buy it.

I know how to determine simple static loads, but I have never learned anything about dynamic loads.

Those figures were taken from our bearing book.

I agree with you that the parts are never seeing more then 9000 ft-lbs, and I believe that is because their is not a real life situation that I have seen that can hold on to a tire for more than 9000 ft-lbs of torque.

BigMike

[blackdiamond]

Is the torque split 50/50 at the transfer case?  Larger tires would also allow more moment/torque resistance to be applied on the axle.

If the static loads are bearing loads then I have no idea how to calculate.  I was thinking that it was the load required to break a tooth on the gear (the smaller ones that are in the "5.0" set) and a calcualtion could be done by multiplying the load by the radius of the gear.

Statics and Dynamics or Mechanics is a great way to spend a year in class, it will either force you to develop study habits or look for employment elsewhere.

My 1st quarter of my 3rd year at Walla Walla was the hardest.  I was taking Mechanics of Materials (2+ hours a day), Linear Network Analysis (2+ hours a day), Ordinary Differential Equations (2+ hours a day) and Fluid Mechanics (8+ hours once a week).  The time was in addition to class time (4 days a week for each) and a 3 hour lab.  Plus I was working at night.  LNA kicked my tail and the next class in line, Feedback and Controls, caused me to switch from Mechanical to Civil.  I figure that if I spent 40+ hours a week on that one class for 3 or 4 weeks and I understood ZERO & ZIP there wasn't much hope of understanding. 

[BigMike]

No, the torque split at the t/case it not 50/50. The rear output should have more torque output because it is just a straight shaft with two bearings, where as the front output has to take power from this same 2-bearing shaft, transfer it to a counter gear with 2-bearings, and then transfer it again to the front output gear that has another 2-bearings.

So there is more friction between gear contact and bearings, and also more weight through more moving parts and more oil to move through....

Well you can figure out how much is needed to shear the teeth from a gear, but there are many other underlying forces, especially with helically cut gears, the gears are repelling each other latterally, or to the side, so there is an enormous load on the bearings, not only from rotational forces, but from also sustained forces that are needed to push back against the gear that is trying to move latterally.

[wa4x4]

        


My head hurts.



That is all.

[hudlenutz]

I know how to determine simple static loads, but I have never learned anything about dynamic loads.

Those figures were taken from our bearing book.

BigMike, those sound like engineering classes, what's your major?  I'm ME.

Anyway, load ratings for bearings are standardized throughout the industry.  So you get your design together, assign a bunch of rating factors, only somewhat arbitrarily, then you compare against the load ratings.  The big failure points for bearings concerning machine design are surface fatigue and brinnelling.  C_s is the basic static load rating, and gives you a feel for the bearing's resistance to brinnelling, and C_d is the dynamic load rating and it covers the bearing's restance to rolling surface fatigue.  You should be able to get these numbers from just about any bearing manufacturer.

Brinnelling is when the pressure on the balls or rollers is enough to plastically deform the bearing race, causing a bunch of unwanted noise, vibration, and other bad things.  Surface fatigue is when the bearing has been used long enough that little cracks begin to form on the race, and it eventually fails... catastrophically.

From a book by Collins, "Based on extensive experimental data [we have no idea where this formula came from, but it seems to work, so don't go askin' too many questions], the relationship between radial bearing load P and bearing life L (revolutions to failure) for any given bearing is

L/10^6=(C_d/P)^a

where a=3 for ball bearings and a = 10/3 for roller bearings"

So for a crawler, you would need to know the number of teeth and pitch of each gear, to calculate the radial load based on the input torque, and you could calculate about how long your transfer case will last when it comes to failure by surface fatigue.

th th bthe that's all folks!

[Tom]

Just a little info (from a graduated ME in the business).  You cannot simply multiply the hp ratings of the engines.

"Using your logic, 22R: 3.93 x 2.28 x 96 hp & 129 tq = 860 HP & 1156 TQ to the 2nd transfer case.  I wouldn't run a stock toyota transfer case behind an 860 hp engine, but...isn't the reason they survive because they don't have impact loads at crawl speeds?"

They will not change across the gears.

HP = Torque x RPM / 5252

For example:

If an engine produces 150 lb-ft at 4000 rpm, then it would produce (4000/5252)*150 = 114.242 hp

If we run that through a tranny with 4:1 first.

The torque output of the tranny is 600 lb-ft, but at only 1000rpm.

Therefore the hp is (1000/5252)*600 = 114.242hp.

Hp cannot be created by gearing, it is always constant (without taking friction and heat into consideration).

Gearboxes are usually rated at input torque and output hp with a max rpm.  (I am going off memory, I may have the torque and hp rating backwards.)

Tom

[blackdiamond]

Just a little info (from a graduated ME in the business).  You cannot simply multiply the hp ratings of the engines.

"Using your logic, 22R: 3.93 x 2.28 x 96 hp & 129 tq = 860 HP & 1156 TQ to the 2nd transfer case.  I wouldn't run a stock toyota transfer case behind an 860 hp engine, but...isn't the reason they survive because they don't have impact loads at crawl speeds?"

They will not change across the gears.

HP = Torque x RPM / 5252

For example:

If an engine produces 150 lb-ft at 4000 rpm, then it would produce (4000/5252)*150 = 114.242 hp

If we run that through a tranny with 4:1 first.

The torque output of the tranny is 600 lb-ft, but at only 1000rpm.

Therefore the hp is (1000/5252)*600 = 114.242hp.

Hp cannot be created by gearing, it is always constant (without taking friction and heat into consideration).

Gearboxes are usually rated at input torque and output hp with a max rpm.  (I am going off memory, I may have the torque and hp rating backwards.)

Tom

I REPENT OF MY WRONG DOING!

I actually had to read that twice to understand the details and note that the HP stays the same (isn't algebra fun ).  Glad to know that there are people out there that know more than me. 

What do you think about the rest of this dialogue?  How much torque do you think Marlin's 3rd transfer case sees in the real world?

"They will not change across the gears." - are you referring to HP here?  This is the one thing I am somewhat confused about.

[BigMike]

I am aware that HP is derived from Torque.

If we run that through a tranny with 4:1 first.

The torque output of the tranny is 600 lb-ft, but at only 1000rpm.

Yes, the final output speed of the tranny will be (Engine speed) / (transmission gear ratio), and the final output torque (theoretically), would be (Engine torque output) x (transmission gear ratio).

HP = Torque x RPM / 5252

For example:

If an engine produces 150 lb-ft at 4000 rpm, then it would produce (4000/5252)*150 = 114.242 hp

But this is only true in linear situations. Two engines can have the same torque output at a given rpm, but have entirely different horsepower curves and rating.

How much torque do you think Marlin's 3rd transfer case sees in the real world?

I know you were asking the other guys, but I just wanted to restate that the "real world" is a very broad question. The real world both combines regular wheeling (where nothing breaks) and then really really stuck situations, where
things do break. So I think that driving on a flat dirt road at 1,047:1 at 4000 rpm there would be nearly the same load on the engine as if it were just in neutural and reved to 4k rpm. So the torque output would be very very low.
But if you are really really really stuck to the point where the ground is completely holding the back tire in a way that either something breaks or the front end is lifted off the ground and the vehicle does a wheelie and flops over backwards, then, at 4000rpm, the load would be much larger, therefore the output of the engine would be much greater (closer to the max output), and now we are talking about 20+ thousand ft-lbs of torque acting on the rear axles, if nothing else up-the-power-line fails.

[blackdiamond]

But this is only true in linear situations. Two engines can have the same torque output at a given rpm, but have entirely different horsepower curves and rating.

But if you are really really really stuck to the point where the ground is completely holding the back tire in a way that either something breaks or the front end is lifted off the ground and the vehicle does a wheelie and flops over backwards, then, at 4000rpm, the load would be much larger, therefore the output of the engine would be much greater (closer to the max output), and now we are talking about 20+ thousand ft-lbs of torque acting on the rear axles, if nothing else up-the-power-line fails.

Horsepower is nothing more than a calculated number so if the torque curves are the same the horsepower curves will also be the same.  I'm not really sure why it would only apply in linear situations since torque curves are almost never linear.  It is true that for an accurate calculation an engine torque curve would be required.

The only way for the drivetrain to provide enough resistance for the engine to actually transfer 20,000 ft-lb would be if everything could handle that kind of torque, and it can't so "really really really stuck" still only will provide about 9,000 ft-lb to the rear axles.

Does it make any sense to look at the motor as a "Potential Energy" source that is, in the real world, unlimited when combined with Marlin's triple cases?

[BigMike]

Horsepower is nothing more than a calculated number so if the torque curves are the same the horsepower curves will also be the same.

Yeah, you guys are right, I am thinking about the power curves, not the outputs...
Apart from the numbers, I always thought that HP was how long the engine can sustain an accelerated pace. Since power is a measure of force/time.

The only way for the drivetrain to provide enough resistance for the engine to actually transfer 20,000 ft-lb would be if everything could handle that kind of torque, and it can't so "really really really stuck" still only will provide about 9,000 ft-lb to the rear axles.

Right, so something would break for sure, either a rear axle shaft, or a weaker link.

I think I finally figured out what you are getting at. If the axle fails at 9000 ft-lbs, then that's it, it will only see 9000 ft-lbs. But I wonder how the energy is conserved? It seems that if you put 1.1 lbs on tissue paper that is rated at 1 lb then you could watch it slowly tear, or you could put 100 lbs on tissue paper that is rated at 1 lb and watch the weight go right through it. I seems that in order for the rate of failure to be accelerated, it will require more energy to do so, and in fact, the 1 lb tissue will actually be pushing back at maybe 2 lbs even, who knows...
But regardless of that, the rear axle will never "feel" 20,000 ft-lbs, but I believe that the potiential that the axle will "see" is more then 20,000 ft-lbs.

[blackdiamond]

Apart from the numbers, I always thought that HP was how long the engine can sustain an accelerated pace. Since power is a measure of force/time.

But I wonder how the energy is conserved? It seems that if you put 1.1 lbs on tissue paper that is rated at 1 lb then you could watch it slowly tear, or you could put 100 lbs on tissue paper that is rated at 1 lb and watch the weight go right through it. I seems that in order for the rate of failure to be accelerated, it will require more energy to do so, and in fact, the 1 lb tissue will actually be pushing back at maybe 2 lbs even, who knows...

Have you read the horsepower vs. torque thread that I posted?  It gives a great explaination.

As for the energy being conserved, the axle starts to yield prior to failure.  The axles that Bobby Long showed me had twisted something like 70 degrees (and was actually no longer straight) before the splines sheared off.  What this means is that the axle was starting to fail (tissue paper starting to tear) before the 9,000 ft-lb was reached and 9,000 ft-lb was the maximum.

Take a look at a stress vs. strain curve for steel (mechanics of materials stuff) and you will get an idea of how materials yield prior to failure.  You will find that when the material yields (starts to stretch) the stress (force/area) stays the same or can actually get lower while the strain (deformation/length) increases until the material yields enough for ultimate failure.  It has been a while since I thought about this so my explaination may not be perfect.  These charts are specifically for tension, but it should be similar in torsion.

Bobbly Long actually posts a similar chart to stress vs. strain, it is torque vs. twist.  Notice that the axle yields (twists) as the torque is increased.  Check out www.toyotasuperaxles.com.

[hudlenutz]

and in fact, the 1 lb tissue will actually be pushing back at maybe 2 lbs even, who knows...

equal and opposite...  the tissue or anything else, can't push back any harder than you're pushing on it, otherwise one of you will move. F=ma

How much torque do you think Marlin's 3rd transfer case sees in the real world?

I was thinking about this too.  It seems there's some debate as to how much torque comes out of a motor, so lets try it from the wheels.  Considering only the rear axle, if you could get all the weight on the rear tires, like at a waterfall or something, and you had the best traction ever, the force you could apply before the wheels would slip would be something like this:

truck~5000 lbs (loaded with stuff?).  Each wheel would carry 2500 lbs of the load.  The friction on that tire would be the load times a coefficient of friction, which is usually less than one, so we'll be optimistic and say one.  So the force of friction on a tire is 2500 lbs.  The torque on the axle shaft is that force times the tire diameter.  Lets assume 37s, so the torque is 1.5417ft*2500lbs=3854 ft-lbs.  We have two tires on this axle, so the diff sees double that, 7708 ft-lbs.  This is reduced by the rear diff ratio (5.29?)=1457ft-lbs from the t-case output.

Under this situation, any more than 1457 ft-lbs out of the rear t-case will only cause the tires to spin.  Certainly this simplified example is not a worst case scenario, but it provides us some insight into the fact that the torque on the drivetrain is probably limited by available traction, and NOT the amout of gear reduction, when multiple transmissions or t-cases are used.