Theories why the Rubicon went with D44s vs upgraded Dana 30/35?

[StG58]

Is it even possible to have the same type of locker that is in the Rubi Dana 44 fit in a Dana 35? Maybe there was an engineering setback that made it more viable to package the Dana 44 with the Rubi locker.

My guess is that the Rubi locker was engineered from the start for the Dana 44. Lockers are pretty axle specific.

I'm also guessing that the whole Dana 44 in a Rubicon thing may have been part engineering, part sales and part marketing. Automotive companies are always coming out with "limited edition" vehicles to get people on the showroom floor. It works both ways too. Someone comes in and says "I want a Rubicon! Gotta get me some of that Dana 44 action", but they end up buying an SE or an X or a Sport because the wife / husband goes ballistic over the cost or whatever. Someone else comes in and says "What's your cheapest Wrangler?" and ends up driving off in a brand new shiny Rubicon from dealer stock. The automotive press has a heyday with the release of the Rubicon, they get to drive a really cool rig around for a couple of days, and write glowing reviews, which drives sales to showrooms. Consumer Reports writes a hit piece saying archaic, anachronistic, uneconomical and unsafe which drives more sales to the showroom floor. It's all about eyeballs and wallets. Buzz words drive eyeballs, and by extension, wallets. Dana 44 is a buzzword.

Think about it, if the Jeep engineers were really serious about off road performance and they are, Dana 60's, 37" tires on bead-lock wheels, and a licensed version of a full Currie suspension would be a factory option on the JK/U's. I'm sure they are that serious, but the bean counters at headquarters and the DOT/EPA folks in Washington would absolutely shut them down in a microsecond.

Maybe the Dana 44 was the best they could get away with in the TJ?

 

[Fouledplugs]

My guess is that the Rubi locker was engineered from the start for the Dana 44. Lockers are pretty axle specific.

I'm also guessing that the whole Dana 44 in a Rubicon thing may have been part engineering, part sales and part marketing. Automotive companies are always coming out with "limited edition" vehicles to get people on the showroom floor. It works both ways too. Someone comes in and says "I want a Rubicon! Gotta get me some of that Dana 44 action", but they end up buying an SE or an X or a Sport because the wife / husband goes ballistic over the cost or whatever. Someone else comes in and says "What's your cheapest Wrangler?" and ends up driving off in a brand new shiny Rubicon from dealer stock. The automotive press has a heyday with the release of the Rubicon, they get to drive a really cool rig around for a couple of days, and write glowing reviews, which drives sales to showrooms. Consumer Reports writes a hit piece saying archaic, anachronistic, uneconomical and unsafe which drives more sales to the showroom floor. It's all about eyeballs and wallets. Buzz words drive eyeballs, and by extension, wallets. Dana 44 is a buzzword.

Think about it, if the Jeep engineers were really serious about off road performance and they are, Dana 60's, 37" tires on bead-lock wheels, and a licensed version of a full Currie suspension would be a factory option on the JK/U's. I'm sure they are that serious, but the bean counters at headquarters and the DOT/EPA folks in Washington would absolutely shut them down in a microsecond.

Maybe the Dana 44 was the best they could get away with in the TJ?

That whole bean counter thing has been proven to be able to be convinced latley. Which is a good thing. Just look at the Hellcat and Dodge Demon. Never would I have thought a manufacture would produce somethig like that. We just need those types of engineers for the Wrangler. Hell they got close with the SRT 8 Cherokee, it is a beast.

Wish the Gen 2 Dana 44's came on the TJ's. Which you can gwt from Mopar. TJK Axles built by Dynatrac for mopar. P5155256 Front TJ P5155257 Rear TJ So I guess you could say we are getting close to a collaboration with some high end off road product builders.

 

[JP98]

The 44 was already part of Jeeps stock room as it was already an option item. As stock it is stronger than the 35. So why not go with it? Some would love to, as @StG58 points out, go down to the dealership and add a Dana 60 as an option but most TJ's rolling would never even come close to needing them. So StG58 is right. It came down to the bean counters, engineers and DOT/EPA folks and Jeep said lest just go with what we have.

 

[Fouledplugs]

The 44 was already part of Jeeps stock room as it was already an option item. As stock it is stronger than the 35. So why not go with it? Some would love to, as @StG58 points out, go down to the dealership and add a Dana 60 as an option but most TJ's rolling would never even come close to needing them. So StG58 is right. It came down to the bean counters, engineers and DOT/EPA folks and Jeep said lest just go with what we have.

I think you nailed it.

 

[StG58]

That whole bean counter thing has been proven to be able to be convinced latley. Which is a good thing. Just look at the Hellcat and Dodge Demon. Never would I have thought a manufacture would produce somethig like that. We just need those types of engineers for the Wrangler. Hell they got close with the SRT 8 Cherokee, it is a beast.

Wish the Gen 2 Dana 44's came on the TJ's. Which you can gwt from Mopar. TJK Axles built by Dynatrac for mopar. So I guess you could say we are getting close to a collaboration with some high end off road product builders.

I've seen those TJK axles advertised and lusted for them. The front axle for the Rubi Recon? Ya, good kit right there.

The Wrangler engineers do hang out on internet Jeep forums, I'd be surprised if there aren't several here, now. It's one of the ways that they can collect input from the public unobtrusively. Heck, we are an extension of the MOPAR proving grounds in a way. Same with the MOPAR marketing folks. They also go to Jeep events and actually drive Jeeps. They get to watch and see what works and doesn't work. Heard a tale from a reliable source that the whole reason that the TJ still had a folding windshield was that one well known and unfortunately now deceased Jeeper with connections to the factory engineers absolutely insisted that the TJ have a folding windshield. Users of a product, especially automotive products, can have a large input into that product.

You can almost imagine the discussion around the lunch table. "Hey, stock Dana 35's are breaking under some circumstances. What's up with that?" "I dunno, what can we do about it?" "Well, we have Dana 44's on the shelf, let's get a team together and see if that will help." "What's marketing and the bean counters going to say?" "Let's fiddle with it and then call Fred to see what he says." I can see it happening. The result is that the Rubi got versions of the Dana 44 for practical and marketing reasons. Everyone, including us, got a win out of the deal.

 

[bobthetj03]

We should consider ourselves lucky the Rubi made it thru the cut.

 

[StG58]

<snip> P5155256 Front TJ P5155257 Rear TJ So I guess you could say we are getting close to a collaboration with some high end off road product builders.

Oh good grief! @Fouledplugs supplied factory part numbers! (scribbling furiously) I need those about as much as I need a new fly reel, but dang! :aplastao::risas3:

 

[Rob5589]

Whatever the reason, it certainly worked. The crazy prices on used Rubicons are evidence of that.

 

[StG58]

Except for Kathy. Kathy got lucky. That was one heck of a deal on a really nice Rubicon.

 

[CasterTroy]

One look at a Dana 30 vs a Dana 44 ring gear answers it for me

 

[StG58]

How many busted ring gears do you hear about though? Spider gears, axle shafts but not to many ring or pinion gears except as collateral damage. With a stock Dana 35, it's axle shafts. Stock Dana 44? Drive lines. The point of failure just migrates around as parts in the system get beefed up.

 

[Fouledplugs]

How many busted ring gears do you hear about though? Spider gears, axle shafts but not to many ring or pinion gears except as collateral damage. With a stock Dana 35, it's axle shafts. Stock Dana 44? Drive lines. The point of failure just migrates around as parts in the system get beefed up.

You may be right about ring gear failures. They are heard about less. When I ran my 35c on 33's I broke spider gears twice. I ride rocks though, so it's admittedly more likely I will encounter issues with a Dana 35. A locker that replaced the spiders could have helped. But it was my choice to go to an aftermarket Dana 44.

You mentioned the drive line being victim after upgrades which bring me to this theory: Maybe with the 4:1 transfer case the engineers had experienced or forsaw issues with the ring gear/pinion/or spiders in testing with the Dana 35. Since it is more torque/stress being applied to the smaller ring gear/pinion/spider gears in the Dana 35 rear end application.

Just a theory.

 

[StG58]

You may be right about ring gear failures. They are heard about less. When I ran my 35c on 33's I broke spider gears twice. I ride rocks though, so it's admittedly more likely I will encounter issues with a Dana 35. A locker that replaced the spiders could have helped. But it was my choice to go to an aftermarket Dana 44.

You mentioned the drive line being victim after upgrades which bring me to this theory: Maybe with the 4:1 transfer case they engineers had or forsaw issues with the ring gear/pinion/or spiders in testing with the Dana 35. Since it is more torque/stress being applied to the Dana 35 rear end application.

Just a theory.

Interesting theory. Makes sense too. The Jeep engineers probably knew that locking a Dana 35 was bad cess for the stock axle shafts, and knew that spider gears were subject to damage from impact loading even with stock, but sticky tires. They would the go to the parts bin for an easy upgrade which would be the Dana 44. Design a limited slip / locker for that and hey presto chango! the Rubi axle is born. I like that theory. How do we verify or substantiate it?

How about that front Dana 44 Rubi axle? Where did it come from? It might tell us something about the thoughts on the rear axle.

 

[Brantley]

One look at a Dana 30 vs a Dana 44 ring gear answers it for me

View attachment 20178

Complete non-issue.

 

[Brantley]

To beef up the stock 35, there are only several ways to do it. Chromoly/1541H 27-spline shafts, 30-spline carbon steel shafts, or 30-spline chromoly/1541H. All of which would require a locker or would require a new carrier case design with better spider gears to not nullify the point of the larger shafts. They would probably pick the locker route since that was how the Rubis came which means they would either have to engineer their own locker (most likely) or buy aftermarket if the aftermarket supports the way they would do the Super 35.

So, which would Chrysler have to choose if they were to go that route? It's clearly a lot easier to just order "stock" (relatively, anyways) 44's than it is to figure out how you're going to beef up a 35 and sell it that way. Would they use Superior's Super 35? Would they use Superior's 27-spline c-clip eliminator? What locker would they give us?

They would pretty much have to be relying on an aftermarket company unless they started manufacturing their own upgraded shafts. That's some extra work for them to do if they can just order what they want from Dana.

Then there is the bragging rights aspect. I am a believer of the Super 35. However, there are plenty out there who don't think it can do a darned thing (they are wrong, but I digress) and so they simply won't go for it because of the age-old phrase "I wouldn't spend a penny on the turdy-five" and because it gives bragging rights to say you have a 44 over any 35. Truth is, a fully beefed 35 with quality components is, in my opinion, actually better than the stock 44 they equipped the Rubicon with, but 44>35 so people want the 44. Also, by the time you fully upgrade the 44, you end up with a larger gear set which is good. Other than the R&P, I consider two beefed up 44's and 35's to be equivalent but the 44 number would sell better to non believers who want nothing to do with a 35.

So, to sum up: bragging rights and lack of good method of manufacture since they would have to purchase thousands of kits aftermarket or engineer their own Super 35 option.

 

[Fouledplugs]

How about that front Dana 44 Rubi axle? Where did it come from? It might tell us something about the thoughts on the rear axle.

Well if a group of automotive engineers decided that the Dana 35 ring/pinion wasnt going to cut it with the more torque from the 4:1 241, it was likely decided through math on paper first. Same way a dodge or any branded 1/2 ton truck gets a certain ring gear diameter in all rear axles.


So on to the Dana 30...with the ring gear being even smaller than the Dana 35 and having the 4:1 241, it may have made mathematical sense to the engineers to upgrade it to match the rear based on some sort of engineering formula or design theory to alleviate breakage. (ex being majority of 1/2 tons having same ring gear diameters.)

Again theory...

Engine HP, Engine Tq, Transfer case gear ratio likely has an impact on ring gear/pinion/axle shaft size in automotive applications. In adition to factors relates to overall weight and tire size.

And we know the engine HP and TQ didnt change, the only part or number that changed was the 241 transfer case.

Working to get some actual evidence or writtings on the TJ rubicon and how it came about and why they chose the parts offered like the Dana 44 over the Dana 35 and possibly how much stronger it actually is from an engineer's POV.

 

[StG58]

Well if a group of automotive engineers decided that the Dana 35 ring/pinion wasnt going to cut it with the more torque from the 4:1 241, it was likely decided through math on paper first. Same way a dodge or any branded 1/2 ton truck gets a certain ring gear diameter in all rear axles.


So on to the Dana 30...with the ring gear being even smaller than the Dana 35 and having the 4:1 241, it may have made mathematical sense to the engineers to upgrade it to match the rear based on some sort of engineering formula or design theory to alleviate breakage. (ex being majority of 1/2 tons having same ring gear diameters.)

Again theory...

Engine HP, Engine Tq, Transfer case gear ratio likely has an impact on ring gear/pinion/axle shaft size in automotive applications. In adition to factors relates to overall weight and tire size.

And we know the engine HP and TQ didnt change, the only part or number that changed was the 241 transfer case.

Working to get some actual evidence or writtings on the TJ rubicon and how it came about and why they chose the parts offered like the Dana 44 over the Dana 35 and possibly how much stronger it actually is from an engineer's POV.

Makes perfect sense! And you da' man if you have the connections to get that narrative!

 

[Fouledplugs]

They would pretty much have to be relying on an aftermarket company unless they started manufacturing their own upgraded shafts. That's some extra work for them to do if they can just order what they want from Dana.

So, to sum up: bragging rights and lack of good method of manufacture since they would have to purchase thousands of kits aftermarket or engineer their own Super 35 option.

I don't believe the engineers at Jeep are directly designing the shafts or determing the lockers used. Please hear me out..I base this theory off the new JK LED headlights, a Mopar option for all JK's (im reaching...I know...far beyond the TJ Rubi) they are built by a contracter, being JW Speaker to meet Jeeps standards. I'm pretty confident that design and decision on the Dana 44 falls to the contractor (Dana) to meet the Jeep engineer's design requirments. They likely approach Dana with their requirements and desires and what it will be used for. Dana comes up with a couple options/builds and the engineers take pick or Again..theory.

Long winded way to say I dont think it is likely Jeep would purchase lots full of aftermart parts to make changes. They would contract it out. Making me theorize that the Rubicon was a design on paper first. Being that it had the 241 maybe it was contracted to Dana to verify/test the 35 could take the extra tq Without breakage. And Dana said noway, based on math theory. And the money could be saved by using the same tube front and rear, front outwrs, and steering u-joints.

I know for a fact that some of the work/options on the new JK's is contracted out at or after the factory. Take that with a grain of salt if you like, as I do not have the support to back it up at this moment.

 

[Fouledplugs]

I believe the Dana 44 in the TJ Rubicon to be more than just a marketing ploy. Yes, the Dana 44 front and rear makes for an awesome selling point. But so does the hellcat's 700 HP and its real and useable.

I am standing by it.

 

[UpperMI]

You want to know my theory? It was a way for the Chrysler to make more money.

One of the number one ways that auto manufacturers make money is by charging people for trim level upgrades (often with unnecessary options). Problem is, with the TJ, there was never really any difference between the trim levels. Look at all of them and they were all pretty basic. Sure, you could get a "Columbia Edition" or whatever, but that was nothing more than some decals, seats, etc.

The Rubicon on the other hand was quite a bit more than the basic TJ, but in order to justify that extra cost, they had to have something to sell. You had the NP 241OR transfer case, the lockers, the better gear ratio, but that's really it. They needed to add something more, and that was the axles. Most people who didn't know any better probably just heard "Dana 44 upgraded axles", and thought, "Wow, that's worth the extra cost!", without knowing they were the same housings as the standard axles (my guess is people didn't realize this until the TJ had been out for a while and they started discovering this first hand).

So that's my theory. I think it was a way to sell an upgraded model and make more money.

When I lived in Detroit, my roommate worked for Bosch and Jack Roush Industries as a mechanical engineer. These are level 1 and 2 suppliers to the big 3 in Detroit. Trim options are where the big 3 make their largest profit margin. To give you an example, a Lincoln Navigator was about $10,000 more on the sticker price than a Ford Expedition. Same platform and essentially the same vehicle. The difference was the badging and the trim levels. The cost to ford was $35 more to assemble a navigator than an expedition. Yes, $35 dollars. And Lincoln would charge $10,000 more. This is why luxury SUV have such large discounts at the end of the year. They can drop the the price with huge rebates and still make money. This was 1998 so my guess in today's dollars it would be In the hundreds of dollars but you get the idea.