[Jeepguy1977]

Originally Posted by Greg_Volkman

that is an opinion. you may be able to dismiss the ring gear size and the 31 spline shafts easily, but that still doesn't mean it is true. until they come out with some real world testing no one will really know.

Wonder who we get to donate to the cause and how to go about the testing .

[Tim]

Originally Posted by Jeepguy1977

Why are you looking at some guys jeep's rear end

hahaha!
i've seen joe's rear axle enough to recognize it anywhere

[GMC7000]

I have an 8.8, how do I tell what year/model it is?

[GMC7000]

on a related note do you think it is worth putting chromolly parts in an 8.8? I know mosier makes 8.8 axles etc

[mrblaine]

Originally Posted by Jeepguy1977

Why are you looking at some guys rear end

Because I can't weld with my eyes closed.

[mrblaine]

Originally Posted by GMC7000

on a related note do you think it is worth putting chromolly parts in an 8.8? I know mosier makes 8.8 axles etc

It is if they are the ones in Superior's Super 88 c-clip eliminator. Not that the c-clips are a problem, but there are several deficiencies the kit addresses.

[never monday]

Originally Posted by Unlimited04

Why breaks something for the fun of it? Do you have that much money that you can afford to? Or are you just breaking other peoples stuff?

First, I haven't broken the S35 in two years, second everyone with an irrational fear is giving me free 35 parts.

Aluminum housings are a totally different story. Again, this fits into the category of alloy of metal used. Those Currie housings and the 44a housing are both very thick aluminum, and very high grade of aluminum at that. Aluminum is actually stronger than steel in many respects, it however does not have the same fatigue life. I'm talking about cast iron and cast/extruded steel when talking about 8.8 vs D44 vs D35 housing strength. A D60 is much heavier than an 8.8 or D44...and much stronger. In general, more material to support stress = more weight and more strength. Sure you can make a lightweight 9", truss it, put 40 spline alloys in it and it will be 1/2 the weight of a D60 and twice as strong, but not many people have a budget for that.

Explain a wimpy Toyota 8" axle running 37 stickies

Don't need an 8.8, I've got a D44

good

I'm a tinkerer. But I'd rather tinker with an educated guess than simply tinker with something for the hell of it. I'd rather run an 8.8 or D44 vs a D35 or S35. Each have their plus and minus, but for where the money goes, I'd rather spend it on something I know is going to last and take abuse.

A 44 is a step up from a S35. I've not denied that. But, a S35 or 44jr is a good viable option for people who can't get a 44 easily. But I still maintain the 8.8 is not a step up from the 44. D44 = 8.8 = S35.
Theres not enough change in strength to justify the expense. Now, moving to 60's or 9" is the next class up.

That said, hopefully we all know the D44 uses the same tubes as a D35, so the tube flex portion of this 'housing flex' is kind of subjective.......

You can add to a D35: alloy shafts, truss, c-clip eliminator, add high quality gears, retube the housing with .25", etc, but its going to cost a lot of money and work. Wouldn't it be smarter (and more economical) to just buy an axle that already has the strength you're looking for?

Your confusing me here. In one sentence you say the 35 axle has the same tube as a TJ44. Then you say to upgrade the tube to .250" It's .250 from the factory.

[Unlimited04]

Originally Posted by never monday

1. Explain a wimpy Toyota 8" axle running 37 stickies
2. A 44 is a step up from a S35. I've not denied that. But, a S35 or 44jr is a good viable option for people who can't get a 44 easily. But I still maintain the 8.8 is not a step up from the 44. D44 = 8.8 = S35.
3. Theres not enough change in strength to justify the expense. Now, moving to 60's or 9" is the next class up.
4. Your confusing me here. In one sentence you say the 35 axle has the same tube as a TJ44. Then you say to upgrade the tube to .250" It's .250 from the factory.

1. Toyota's third member style axles are different that the fully cast housing design of an 8.8, D44, D35 or even the D60. Its more like a 9", and third member housings are notoriously stronger. This is because most often, they are tapered from the center outward, inherently creating a big truss, made of steel, not cast. A third member axle is definitely a better design (for strength anyway) than the standard cast center section with tubes. Plus theres just the fact that Toyota has made better drivetrain components than Dana for a long time. Toyota's 8" third members are pretty cool...high pinion, and can be swaped front to rear, plus the strength of a D60, definitely awesome for field servicability. Lots of big semi-truck axles, including Rockwell 2.5 ton axles, are third member style designs.

2. If a D44 is a step up from a S35, but a 8.8 is not a step up from a S35, then shouldn't it read D44 > 8.8 = S35?

3. hhhmmmm 9"...third members...Spidertrax housing's are sexy

4. I ment .500, reading to much axle specs to keep crap straight. And, TJ D44's tubes are still prone to the same flexing a S35 would be, but the larger center section and larger gears add to strength and lessen the chance of breaking something inside that center section vs a S35.

For future reference - thanks to Google and my trusty calculator:
Dana 30 - 2.5" x 0.250" wall - Moment of Inertia: .65941 in^4
Dana 35 - 2.5" x 0.250" wall - Moment of Inertia: .65941 in^4
Dana 44 1/2 ton - 3.0" x 0.250" wall - Moment of Inertia: 1.16870 in^4
GM 10-bolt - 3.0" x 0.250" wall - Moment of Inertia: 1.16870 in^4
GM 12-bolt - 3.0" x 0.250" wall - Moment of Inertia: 1.16870 in^4
Ford 8.8 inch - 3.25" x 0.188" wall - Moment of Inertia: 1.1614 in^4 (some say .250", but I've never measured one so I'll stick with never_monday's spec)
Ford 9-inch - 3.0" x 0.250" wall - Moment of Inertia: 1.16870 in^4
Dana 44 front 3/4 ton - 2.75" x 0.500" wall - Moment of Inertia: 1.5493 in^4
Dana 60 rear - 3.125" x 0.313" wall - Moment of Inertia: 1.61209 in^4
Dana 60 front - 3.125" x 0.500" wall - Moment of Inertia: 2.3506 in^4
Dana 70 rear - 3.625" x 0.563" wall - Moment of Inertia: 4.1611 in^4

The higher the moment of inertia, the more cross sectional area of material to absorb stress, the stronger the tube.

[never monday]

Originally Posted by Unlimited04

2. If a D44 is a step up from a S35, but a 8.8 is not a step up from a S35, then shouldn't it read D44 > 8.8 = S35?

Agreed
Because the 44 housing is better than a 35 or 8.8

3. hhhmmmm 9"...third members...Spidertrax housing's are sexy

Spiders housings are 3"x .250 and not ramped like you described

Dana 44 1/2 ton
3.0" x 0.250" wall

this is true. But most conversation here is based on the TJ/XJ 44 which is 2.5 x .250

[Unlimited04]

Originally Posted by never monday

Spiders housings are 3"x .250 and not ramped like you described

this is true. But most conversation here is based on the TJ/XJ 44 which is 2.5 x .250

yea, spidertrax housings are in a totally different ballpark, just like Currie RockJocks. Those are for people with lots of money they don't know what to do with! But a good comparison to a Toyota 8" would be the Ford Banjo 9" vs the Ford late model 9". The 8" Yota looks a lot more like the late model 9", which is significantly stronger than the Banjo housing.

I thought XJ D44's were 2.75" and XJ D35s were 2.65", but TJ's were 2.5"? Splitting hairs here, i'm sure Jeep used slightly different size tubes across many of these axles depending on the time period.
http://www.4x4wire.com/jeep/tech/axle/xj_dana44_02/

[never monday]

Originally Posted by Unlimited04

I thought XJ D44's were 2.75" and XJ D35s were 2.65", but TJ's were 2.5"? Splitting hairs here, i'm sure Jeep used slightly different size tubes across many of these axles depending on the time period.
http://www.4x4wire.com/jeep/tech/axle/xj_dana44_02/

ya think?
in the end for 35" tires it doesn't mater which axle you have all 3 are viable axles.

[mrblaine]

Originally Posted by Unlimited04

4. I ment .500, reading to much axle specs to keep crap straight. And, TJ D44's tubes are still prone to the same flexing a S35 would be, but the larger center section and larger gears add to strength and lessen the chance of breaking something inside that center section vs a S35.

It might interest you to know that the D-44 has longer tubes than a D-35. Your trusty calculator knows that for the same diameter and wall thickness in the same material, a longer tube is weaker. Eh?

[Unlimited04]

Originally Posted by mrblaine

It might interest you to know that the D-44 has longer tubes than a D-35. Your trusty calculator knows that for the same diameter and wall thickness in the same material, a longer tube is weaker. Eh?

i was merely comparing cross sectional area, not length. The moment of inertia, by definition, doesn't care about the length of a tube.

I didn't compare tube length at all, but had assumed the D44 shafts would actually be shorter in the same configuration, since the D44 housing is larger & track width is still the same, or at least less bare tube would be exposed. Assuming we're comparing disc and disc and drum to drum axles.

What is the difference between the tube lengths of each side? What is the overall tube length of each axle? I could calculate the stress on any length tube using beam bending. For tube strength ONLY, if the overall difference between them is less than 1 to 2 inches, i'm going to guess 8.8 > D44 > D35 based on moment of inertia (MOI), since the 8.8's MOI is almost twice that of the D44/D35 tube. **based solely on tube strength! not overall housing strength**

[never monday]

I think your still missing real world impact strength of .250 Vs .188
Yes the 3.25x.188 tube will take more to bend. But how about impact resistance when you miss judge the height of the rock in the road at 30-40-50mph. This is where the thicker wall will shine.

[Unlimited04]

Originally Posted by never monday

I think your still missing real world impact strength of .250 Vs .188
Yes the 3.25x.188 tube will take more to bend. But how about impact resistance when you miss judge the height of the rock in the road at 30-40-50mph. This is where the thicker wall will shine.

Why would anyone hit a big rock at 30, 40 or 50 mph? You'll loose control of the vehicle no matter what rear axle you have. On the street, everybody (hopefully) avoids everything thats not pavement...this keeps tires from blowing and alignment straight, thats a true generalization for all vehicles, not just TJs.

Impact resistance? It still boils down to shear and stress over a specific area. The more area said shear and stress has to distribute long, the stronger the part will be. Also - impacts get into something a lot more complicated, including non-linear differential equations, but again...it still boils down to force per unit area. Thats why birds have large diameter hollow bones - stronger and lighter. Same with your bones...large diameter & thin cortical wall.