Anyone here running this combo with 38" tires. Just wondered if I was going to have trouble with the dana 44 breaking axle shafts.:confused:

I ran 36 sx's on an open 44 and spit out ujoints all the time. Then upgraded to a 60 and 40" boggers and had no problems

rear 60?
last year I broke 1 rear 60 axleshaft and 3 d44 fronts on tires about 38

depends on what you are doing.

If you are crawling it all the time yeah, you are gonna break shafts all the time. If you have a big block and a heavy truck then yes, you are gonna break both front and rear shafts.

But if you are just doing easy trails and muddin then you will see less breakage.

Dude, if your wheelin hard your gonna break anything you have! Know your limitations and be smart and it will be fine, yeah it will break once in a while but anything will. I have a dana 44 in a light truggy ran 39.5 boggers and tsl's in everything from mud to rocks to hardcore trails. i put some je reel u-joints in and since then only broke one outer. just my experience, if you have a 60 or access to one great if not dont sweat it

I have broken D44/10 bolt axle shafts more than enough times. The biggest tire I have ever run on a 44 is a 35" and I broke the shaft like candy (inner and outer). I have broken them with even 31" tires....:barf:. And even a couple times with a carbed 4.3 V6. I personally hate 44's and would never run one unless it was under something light like a jeep. Right now I am in the process of swapping a 14bolt and D60 combo under my DD which never leaves the pavement.....just for peace of mind.

Carry some extra shafts, hubs, U joints, ... shit carry extra everything...

It's gonna blow up, it's just a matter of WHEN

Right now I am in the process of swapping a 14bolt and D60 combo under my DD which never leaves the pavement.....just for peace of mind.

Sounds like you got a heavy foot:flipoff2:

Sounds like you got a heavy foot:flipoff2:

You might be right. :smokin:

i ran a 44 front with 38s for 3 years and not once did i complete a trail with the all the same shafts in that piece of shit axle. every trip there was at least one broke axle, and thats with a tired old 350 and a light foot.

If this horse ain't dead, it sure is hurtin'.

Weight, drive style, terrain, gear reduction, trans type, etc...

I popped several D44 joints/shafts, and a balljoint w/33's, 2:1 low, and an auto behind a reasonably mild 400SB in my 3/4-ton before I got sick of it and swapped in a D60, but I run it fairly hard. It all depends...

Personally, I wouldn't do it if I were you, but then I can't stand to have to baby my junk and pucker every time I turn the wheel. If it breaks doing what I need it to do, it wasn't built heavy enough in the first place and needs to be beefed IMHO. Why run something weak that you have to constantly nurse, worry about, and overhaul while jammed in the rocks or buried in a swamp-hole?

To answer your question, no, I wouldn't run 38s on a D44 but plenty of guys do it and claim to get by...

Carry some extra shafts, hubs, U joints, ... shit carry extra everything...



:laughing:
:laughing:
:laughing:
:laughing:

forget what these douche bags say, run what you got then upgrade. if you do mud and trails 80-90 percent of the time you'll be ok. i ran 36's w/a d30 and didnt know what takin it easy was then went to a d44 w 38's and gave it more. weight matters and so does traction but just run it, no ones likes to break parts or try to limp in, but if 100 people tell you it wont work and 100 people tell you it wont, what are you gonna do. sit around watchin or play?

Weight, drive style, terrain, gear reduction, trans type, etc...


All depends on a lot of factors. Like someone else posted. You CAN break anything...

forget what these douche bags say
:shaking: u used your first post here to tell all of us who have chimed in with our first hand experience (which, is exactly what he ask for) to call us douche bags?

HAHAHAHAHAHA That's funny!

My friend has a Scout with a tired International V8 in it and its running 44's front and rear with 37" boggers. He's wheeled it a couple times since he got it and has only blown up a stub and a hub so far. The front 44 has a posi and the rear is spooled. I think your going to see some issue if you try to get on it with 38's and a D44 front under a fullsize.

when i had 1/2tons under my k5 with 35s i never broke anything, but i had open end. i wouldnt trust a 1/2ton axle with 38s for long, and definitely not if its locked.

What is considered light? Also are we talking 10 & 20 year old parts that are breaking or new alloy stuff? I'm just trying to get a clearer picture. Thanks.

i ahve 39.5x15 tsl's and i have a front d44 only thing ive broken is the 2 spiders out of the carrier..........i consider what i wheel to be moderate difficulty

YOU PANZYS...lol...I had a 10 bolt on the front of my SUBURBAN and 42's and wheeled the piss out of it in some nasty mudholes...It took me approximately 3 months to DESTROY the axle.. broke axle knuckle ball joints brake line and steering all in one shot...I finally saved and scored a deal on a completely new dana 60 for 1200 bucks....

YOU PANZYS...lol...I had a 10 bolt on the front of my SUBURBAN and 42's and wheeled the piss out of it in some nasty mudholes...It took me approximately 3 months to DESTROY the axle.. broke axle knuckle ball joints brake line and steering all in one shot...I finally saved and scored a deal on a completely new dana 60 for 1200 bucks....

YOU PANZYS...lol...I had a 10 bolt on the front of my SUBURBAN and 42's and wheeled the piss out of it in some nasty mudholes...It took me approximately 3 months to DESTROY the axle.. broke axle knuckle ball joints brake line and steering all in one shot...I finally saved and scored a deal on a completely new dana 60 for 1200 bucks....

well sweet double post...


What is considered light? Also are we talking 10 & 20 year old parts that are breaking or new alloy stuff? I'm just trying to get a clearer picture. Thanks.


alloy stuff is aftermarket (yukon, superior, mosier, etc) that is in a whole different league. What people here are talking about (assuming but close i believe) are all stock components. That is cheap u-joints or spicers, stock shafts, ring &pinion, etc. when you go alloy its a whole nother ball game, different park.

I could be wrong, but I find it hard to believe that even a "built to the hilt" alloy everything D44 would be as strong as a stock D60 in good condition w/good, non-neckdown Spicer shafts and the new Spicer joints. Upgrade to D70 stubs and 35 spline lockouts or pucks and you've got a tough axle. Why build a D44 all the way just to approach the strength you would have in a stock 60 unless you just desperatley need the clearence or weight savings? You have nowhere to go from there if you need more beef in the future but if you have a stock 60, you can go for alloys, CTMs, and so on.

To each, his own. If you can get your D44 (or 10b) to live a long and happy life, well that's just the cat's ass. I couldn't (or at least didn't want to have to always try) so I upgraded.

BTW, nice 1st post dipshit. 36s on a D30? You must have never gotten your power-wheels jammed up against one of those wicked-nasty parking lot islands before.

You'll make friends in no time...
:shaking:

i ahve 39.5x15 tsl's and i have a front d44 only thing ive broken is the 2 spiders out of the carrier..........i consider what i wheel to be moderate difficulty
yeah, but how many weeks have you been wheeling that thing?

I must have posted this 30 times various places on here, but here it goes one more time (sorry to all of you who read my posts in other threads regarding this)...

For hard use with a locker, stock D44/10 bolt front ends are good to 31-33" tires max, provided you weld the u-joint caps into the axle shaft ears. We break stock welded shafts with 31's all the time. Anyone who tells you it's safe to run 38's on them is not using them very hard, or has a samurai with a stock motor & no low range kit in the t-case.

If you run ctms & 4340 shafts in your D44, you can get away with 35-37" tires (depending on vehicle weight) if you drive with a bit of discretion. We broke a 4340 shaft this weekend with 35's on a TJ with a stock 4.0. They are certainly not bombproof, but they will hold up if you are careful.

Anything bigger than 37" (or 35" on a heavy vehicle) absolutely requires a D60 with 35 spline stubs. No way around it. Sure, you might be able to drive around on dirt roads with tires that big on a D44, but you're not going to do any serious wheeling with it.

Serious abuse (competition) with tires above 37" calls for 35 spline 4340 shafts & ctms in your D60. Some of the guys are using the Bobby Long Birfields or even the huge Sunray 1600 series stuff, & 40 spline axleshafts.

Hope that helps give you a realistic view of what will hold up. Anyone who is telling you a locked stock D44 will live with 38" tires & heavy use is living the impossible dream.

Hans

at least 80% of the people on here dont abuse their stuff as bad as you do. most of us are not competing, and your estimates are a little extreme for like i said 80% of us. i personally know that with my driving style i could easily run 38's with a front 44 and rear 60. you dont have to be abusive to be "hardcore".

use a little wisdom and you can make it survive. but if you are "hardcore" or have a heavy foot (which i do not) then break it, and then you will know why we say upgrade.

I don't compete, just recreational wheelin'. I use my stuff hard but I try not to abuse it.

With a 10-bolt front axle with a limited slip, 30-spline shafts, and Spicer joints I broke the front u-joints twice with 35" tires.

After swapping to a stock Dana 60 front with a Lock-rite and 38x13 TSL's it held up better but still broke. A necked down inner and two 30-spline stubs completely broke at different times. When I replaced the stubs with 35-spline chromo this spring I found another one of the 30-spline stubs twisted pretty bad.

I've also wheeled with a couple guys running Jeeps with 4.0's, low geared t-cases, and locked Dana 44 fronts with 36" tires. I don't think they have broke anything in the front, but they are also the type who uses their stuff hard but do not beat on it. Neither one of them wants to go to bigger tires because of the fear of breaking stuff.

I also wheel with a couple of Toyota guys regularly who have built 'yota front axles (chromos, blingy birfields, etc...). I'm guessing these are pretty equivalent to D44 strength. One has 37's and one skinny 38's, they hold up decently but I have seen both grenade the front ends pretty good.

The basic conclusion is that I think you can get away with a Dana 44 front on a light vehicle on 38's IF you take it fairly easy and keep up on the maintenance. It's definitely not bullet-proof and can break anytime though.

at least 80% of the people on here dont abuse their stuff as bad as you do. most of us are not competing, and your estimates are a little extreme for like i said 80% of us. i personally know that with my driving style i could easily run 38's with a front 44 and rear 60. you dont have to be abusive to be "hardcore".

use a little wisdom and you can make it survive. but if you are "hardcore" or have a heavy foot (which i do not) then break it, and then you will know why we say upgrade.

you must drive way better then me.
I snapped 4 d44 shafts and a rear d60 30spline shaft last year babying the Daily Driver.
hoping alloys will make it last longer before resorting to sliding back down to 35s, where I could still snap shafts almost at will.

have a coouple of d60s here just have to do the work

Just curious what weight your rigs are and how much torque are your engines pushing to snap those D44 like toothpicks?

I have been considering a D44 swap under my 3,500 pound S10-Blazer with a whooping 150ft pounds of torque from that torque monster 2putt8 engine.

Just curious what weight your rigs are and how much torque are your engines pushing to snap those D44 like toothpicks?

I have been considering a D44 swap under my 3,500 pound S10-Blazer with a whooping 150ft pounds of torque from that torque monster 2putt8 engine.
tired 20 year old tbi 350 with t400 and 203/205 and 4.10s. in a halfton.

i even broke my chromo 44 inners. and i was always gentle on the throttle.

Just curious what weight your rigs are and how much torque are your engines pushing to snap those D44 like toothpicks?

I have been considering a D44 swap under my 3,500 pound S10-Blazer with a whooping 150ft pounds of torque from that torque monster 2putt8 engine.

The 4340 stub we broke this past weekend was on a gutted 2001 TJ with a bone stock 4.0. & 35" tires. It did have a manual tranny, 3.8 atlas, & 4.88 gears, which is admittedly far too much load for a D44, regardless of what parts are in it. It took out the detroit when the shaft let loose as well.

Stock D44 shafts break at around 5,000 ft/lbs of torque (about 500 ft/lbs above a stock 5-297X u-joint in the straight position), while 4340 D44 shafts are good up to around 11,000 ft/lbs. A D44 warn premium lockout lets loose around 6500 ft/lbs. A 5-297X size CTM is good to over 15,000 ft.lbs.

Do the math & you'll see... with low gearing it's not hard to generate enough force to break any one of these components, especially if the vehicle is bouncing, jammed into a rock under power, or otherwise subjected to a shock load.

Since we're doing the numbers thing, a few more for you - A Stock 35 spline D60 inner axle breaks around 10,000 ft/lbs. A stock 30 spline D60 stub lets loose at a measly 6000 ft/lbs. A 4340 35 spline D60 inner shaft is good for around 15,000 ft/lbs, and a D60 CTM can take well over 20,000 ft lbs.

Obviously, with hard use , low gearing, power, & abuse - you can break anything. Your only saving grace is that the shafts tend to flex a bit and the tires will lose traction at some point, unless they are wedged in a hole.

Hans

you must drive way better then me.
I snapped 4 d44 shafts and a rear d60 30spline shaft last year babying the Daily Driver.
hoping alloys will make it last longer before resorting to sliding back down to 35s, where I could still snap shafts almost at will.

have a coouple of d60s here just have to do the work
i had a FS bronco with TTB 44 w/ ez locker and welded 8.8 rear. i ran 35's with a granny low 4 speed, and a 2.7 t-case with 4.56's in the diffs. i never once had a problem. that doesnt mean that i wouldnt have a problem eventually, but that with my particular driving style i could make them last a lot longer (especially with proper maintainance). currently i decided not to try and even wheel my 10 bolt and went straight for a 60. this is me trying to be over built, not built to my needs, but built beyond it so there is very little chance i will have a problem. right now i have 38.5 tires. will i break an axle? (according to HS, the probability is high), i highly doubt it. i plan on taking it up to a 42 next time i get tires, will i break then? probably not. it is not because of a lack of "extreme wheeling" but because i choose to find the path of least resistance. i am not out there to compete like HS, which is why i assume he is as hard on stuff as he is. but i am out there to have fun and enjoy what wheeling is all about. i dont like to be hard on my junk, unless it is critical that i am. parts are expensive and if i can take a slighly different line so i can eat next month, then i will.

this arguement will never end. it is because of different driving styles, different terrains, and different vehicles. i forgot to mention that i will be running a 700r4. its not what i want in the long run, but i highly doubt i will do any damage to it. i do plan on swapping it out for a 400 when i go dual cases, but that is for insurance mostly. that and the fact that i wont really need OD.

The 4340 stub we broke this past weekend was on a gutted 2001 TJ with a bone stock 4.0. & 35" tires. It did have a manual tranny, 3.8 atlas, & 4.88 gears, which is admittedly far too much load for a D44, regardless of what parts are in it. It took out the detroit when the shaft let loose as well.

Stock D44 shafts break at around 5,000 ft/lbs of torque (about 500 ft/lbs above a stock 5-297X u-joint in the straight position), while 4340 D44 shafts are good up to around 11,000 ft/lbs. A D44 warn premium lockout lets loose around 6500 ft/lbs. A 5-297X size CTM is good to over 15,000 ft.lbs.

Do the math & you'll see... with low gearing it's not hard to generate enough force to break any one of these components, especially if the vehicle is bouncing, jammed into a rock under power, or otherwise subjected to a shock load.

Since we're doing the numbers thing, a few more for you - A Stock 35 spline D60 inner axle breaks around 10,000 ft/lbs. A stock 30 spline D60 stub lets loose at a measly 6000 ft/lbs. A 4340 35 spline D60 inner shaft is good for around 15,000 ft/lbs, and a D60 CTM can take well over 20,000 ft lbs.

Obviously, with hard use , low gearing, power, & abuse - you can break anything. Your only saving grace is that the shafts tend to flex a bit and the tires will lose traction at some point, unless they are wedged in a hole.

Hans
im glad you posted some of those numbers. i would be interested in knowing more if you had them. things like that are good to have when brainstorming for a vehicle.

Just curious what weight your rigs are and how much torque are your engines pushing to snap those D44 like toothpicks?

I have been considering a D44 swap under my 3,500 pound S10-Blazer with a whooping 150ft pounds of torque from that torque monster 2putt8 engine.


'76 longbed, reg. cab 3/4-ton w/ mildly modified 400SBC (cam, intake, carb, headers, full duals) probably making around 400 lb-ft give or take, TH350, NP203, 4.10's, 33' tires (not for much longer...:D). Snapped D44 joints quite regularly w/ relatively mild wheeling/ pulling. Sinse the D60 swap (and swap to 4.56's), I have run it MUCH, MUCH harder, and have yet to have a problem. Not saying it can't happen, just hasn't happened yet.

I'd say that a D44 would be a pretty decent axle for an S-10 if you aren't gonna really beat it to death. I just think is't too small in every respect for a hard working fullsize.

HSOFFROAD- Do you have ratings for the 4340 30 spline stubs?

Stock D44 shafts break at around 5,000 ft/lbs of torque while 4340 D44 shafts are good up to around 11,000 ft/lbs.

Since we're doing the numbers thing, a few more for you - A Stock 35 spline D60 inner axle breaks around 10,000 ft/lbs. A 4340 35 spline D60 inner shaft is good for around 15,000 ft/lbs...Hans

Not saying you are wrong, but why would an alloy D44 shaft be more than twice as strong as a stocker, but an alloy D60 shaft would be only 50% stronger than a stock shaft? Shouldn't the strength increase be about even (percentage wise) between the two when upgrading to the stronger 4340 material?

I'm taking the numbers from various books & things I have read, regarding real world testing of parts. I rounded the numbers from memory in the last post, and looking at the chart now I was off by 1000 ft/lbs on a few of them. In real world useage, the numbers aren't perfect anyway.

As many of you know, often times by the numbers you should break one part, but you break another instead. As axleshaft length changes, so does the ammount of twist in it for a given load. This changes the ammount of shock torque it can take. Also most axleshafts neck up or down and it's hard to assume their actual diameter, other than in their smallest or largest areas. And that's not accounting for the different quality of steel used by different shaft manufacuturers, hardening processes & depth, and material thickness in the area around the u-joint caps in front axles. The numbers I provided aren't absolute indesputable rules, but they are good baseline figures to work off of.

At any rate - here is the axleshaft chart that I originally used to derive the strengths for the axleshafts. Take it and apply it to the diameter axleshaft you are using to determine approximate break strength. If you want, I can try to hunt down the actual written infor for the other stuff I listed, but I know that it is all pretty close to accurate.

1.10" 1040 steel (neck down section of a stock D44/10 bolt shaft) - 3639.8 ft/lbs.
1.125" 1040 steel (OE D44/10 bolt stub axle) - 3787.5 ft/lbs.
1.28" 1040 steel (OE 10 bolt inner) - 5,571.4 ft/lbs.
1.28" 4340 cro-mo - 9,147.4 ft/lbs.
1.31" 1040 steel (OE 44 Inner) - 6044.1 ft/lbs.
1.31" 4340 cro-mo - 9,923.5 ft/lbs.
1.37" 1040 steel (stock 14 bolt semi-floater shaft) - 6,828.4 ft/lbs.
1.37" 4340 cro-mo - 11,211.2 ft/lbs.
1.50" 1040 steel - (stock 35 spline D60 inner/35 spline stub) - 8,966.2 ft/lbs.
1.50" 4340 cro-mo - 14,721.2 ft/lbs.

To determine the static load a given part sees, multiply the peak torque output of your engine, by the torque multiplication items leading up to it. For an axleshaft it would be engine torque X tranny first gear X T-case low range X ring & pinion ratio. (For automatics, multiply the first gear X2 to account for the torque converter). Then take the final number and multiply it by 0.85 (to account for approx. 15% loss due to friction, parasitic drag, & the like.)

Shock loads (bouncing the truck while the wheels are spinning at a high speed) can easily multiply these figures 3-4 times. Mathematically, you will see that as you increase torque multiplication, the numbers quickly skyrocket well above the break strength of even the strongest D60 parts.

Your saving graces are that A - you can control throttle input & use. You don't have to always feed the engine's maximum power to parts, and you can let off the gas pedal if it starts to hop & bounce. Not that it's the most fun or effective way to do things, but you can regulate throttle input. And B - tires can slip. This is why increasing the grip the tires have (by using larger, wider tires, or using them on grippy surfaces such as rocks) is so much harder on axleshafts. Unless it's hoplessly wedged in a hole between rocks, a 31X10.50R15 will generally slip well before the yield strength of a D60 axleshaft. By the same token, a stock 10 bolt axle shaft will break long before a 44X18.5-15 swamper will slip on a grippy surface. This is how the tire size ratings for a given axle are derived.

Hans

wow good info

instead of studying for my developmental econ exam in two hours i am reading this and i have to say i am probably learning more here then i would in a book about economics.

I'd say that a D44 would be a pretty decent axle for an S-10 if you aren't gonna really beat it to death. I just think is't too small in every respect for a hard working fullsize.


I would agree. I have a '00 s10. 4l60e auto with upgraded 233 t-case (no 4:1 though) it's got a HP D44/9" under it. 37" MTRs, 4.88s, lockright/mini-spool, Yukon 4340s in front with 760s, stock 31 spline rear. fairly stock 4.3 (apprx 200hp/260ft-lbs due to a few mods). I wheel it hard all the time and it's a DD as well (not by choice, just can't afford a towrig/third vehicle). I don't wheel it stupid though. I'm only hard on the gas when it's called for yet I always try the tougher line since I like to challenge myself and the truck.

have not broke anything in 2 years so far, though I think it's time for new balljoints here soon.

it seems that properly built, the D44 should hold up fine for lighter rigs like the Toys, Jeeps, S10s, etc.. but the extra weight from the fullsizes would probably push it over the limit even with a smaller tire.

I'm no expert, just my take on how my rig is holding up ;)

btw Hans, cool website. lol@ the deranged feline!

...As many of you know, often times by the numbers you should break one part, but you break another instead...

this is usually the case. i know a guy that twisted a square tube driveline but didnt break the 1310 u-joints attached to it.

Good info. ::Click--drag--right in the "truck" file:: Just don't sue me for copyright! :D

So the common concensus would be that a 4340 30 spline D60 outer would be about the same strength as a stock, non-neckdown D60 inner? I would like to keep my stubs 30 spline so that I can use stockers for trail spares and so I can also keep my Spicer lockouts, but the stock outers are the only things that really make me nervous about my front axle. I don't need full cro-mo shafts for my purposes, but those little stubs are a big weak link. I don't have any spare spindles at the moment if one explodes...

Do you have the numbers for the newest so-called "cold forged" D60 Spicer U-joints?

Do you have the numbers for the newest so-called "cold forged" D60 Spicer U-joints?


No, but I do have info for the 5-297X size joints & 1310-1350 driveshaft joints.

A stock 5-297X spicer joint is generally good to between 4000 & 4500 ft/lbs when straight.

When angled at full lock (35-40 degrees), strength is reduced by roughly 25%. Therefore, at full lock a 5-297X should break between 3000 - 3375 ft/lbs.

The new spicer cold forged joints claim 20% strength increase over the std 5-297X. Doing the math, that comes out to 4800 - 5,400 ft/lbs when straight & 3600 - 4050 ft/lbs at full lock. If correct, that's substantial - it means that at full lock, the new joints are almost as strong as the old ones when pointed streight. Personally, I haven't seen them prove to be all that much better than a 5-297X. They still break in the places where the old ones did. And of course, the ears of the shafts still ovalize & rip off .

A 5-297X size CTM exceeds 15,000 ft lbs when straight and 11,000 ft lbs at full lock. This is why you never see anyone breaking a ctm u-joint unless they weren't maintained properly.

As for the D60 stuff, I have no info, but if you can get a baseline number for straight break strength, you can use the above info and apply it to the D60 joint. Everything is the same, including the claimed 20% strength increase.

Now for the driveshaft u-joint continuious torque ratings (sorry, I can't find the break-torque numbers, I'll keep looking):

1310 - 1,600 ft/lbs contiunous torque
1310 - 1850 ft/lbs continuous torque
1350 - 2260 ft/lbs continuous torque

Hans

Great info!!!!

I did the math on my rig. 150x6.12x2.72x3.73x.85=roughly 7,900. Which puts me in the D60 range, yet based on everyones expierence the D44 will be fine for my use. Makes me wonder how my stock IFS has survived for so long? Unless I did the math wrong.:skull:

That's figuring absolute maximum possible torque output. If you got your wheels totally and completely locked so they would not slip, and got your engine revved to peak torque output and held it there, you very likely would pop a shaft. In fact, I popped one of many D44 U-joints almost that way trying to pull a stump once. Wheels straight, low range, lots of 400 SB torque pouring through the driveline with no wheel spin...BANG! No rocks though. Fortunately, that doesn't often happen, and can be avoided if you're careful. I had a 3/4-ton work truck, and the damned stump needed pulled! I wasn't careful, but if it won't do what I need it to do, it's just not built heavy enough.

Anyway, I'll bet a lot of guys are running axles not capable of tolerating the maximum possible torque output of their drivetrains. I know I was in my old Cherokee (360, T-18 w/6.something to 1 low, model 20 T-case, D44's F+R), but I only broke one joint on it, and it was on death's door to begin with.

Well it's not exactly the "maximum output" as you say... not by a long shot. If you have the tires spinning at high speed (creating tons of potential energy)... and then all of a sudden they encounter resistance... the static number that the engine produces can easily be multiplied by a factor of 3-4. That would mean that his number of 7900 ft/lbs. can easily become 31,600 ft/lbs if he is hopping the truck attacking an obstacle at full throttle and a tire bounces into a hole. Like I said earlier, no axleshaft used in 4wd applications will survive those kinds of loads. If a tire dosen't slip, you WILL break a shaft.

There is some flex in the shafts to help absorb shock loading, but regardless of what kind of axles you ar running... if you jam a tire & stand on the gas in a 4x4 with low gearing - something is going to break.

Hans

this axle setup is for my 83 cj5 jeep w/ the stock 304 and a 3 speed manual trans. I really don't have much money invested in these axles and plan to upgrade to a Dana 60 as soon as I can sell off a couple of my kids and can afford it. I guess I'll just put them in and give them a try. Thanks for all the help.

Matt

Well it's not exactly the "maximum output" as you say... not by a long shot. If you have the tires spinning at high speed (creating tons of potential energy)... and then all of a sudden they encounter resistance... the static number that the engine produces can easily be multiplied by a factor of 3-4. That would mean that his number of 7900 ft/lbs. can easily become 31,600 ft/lbs if he is hopping the truck attacking an obstacle at full throttle and a tire bounces into a hole. Like I said earlier, no axleshaft used in 4wd applications will survive those kinds of loads. If a tire dosen't slip, you WILL break a shaft.

There is some flex in the shafts to help absorb shock loading, but regardless of what kind of axles you ar running... if you jam a tire & stand on the gas in a 4x4 with low gearing - something is going to break.

Hans


Well of course it's not the maximum amount of STRESS that could possibly be placed upon the axles, but what he was referring to was the torque multiplication possible using engine torque multiplied by gear ratios ALONE. What I was saying is that many rigs with decent crawl ratios can theoretically surpass the limits of their axles by engine torque x gearing alone, or the "maximum output" of the drivetrain (no shock loads necessary). Of course shock loading can multiply this many times. Such as if you ran a vehicle up to 160 MPH on jackstands and then knocked it off onto a patch of VHT covered cement. A Briggs and Stratton 5-horse could theoretically create thousands of pounds of shock loading given the proper conditions. That wasn't my point.

thanks guys!!!!

That cleared up a few things.