2024 full float axle strength/pricing?

[Joaquim]

Just can’t justify the price/insurance cost of the 392 so I’m debating getting a current gen rubicon V6 - but the full floats on the 24 are tempting enough to make me wait. Anybody got any idea as to the specs or strength of them? Does them being full float mean it’ll have hubs where the axle shaft is easily accessible? Any info on pricing anywhere?

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[FreedomFur]

I was thinking of watching to see if a takeoff 4.56 showed up in the market in NH. I am geared for 4.56 in the front and rear currently. But wouldn’t want to bother going any higher with the D44 axles since the gear teeth would be getting too small real quick. If that is the direction its heading, might as well get a D60 or bigger.

 

[fat_head]

I was thinking of watching to see if a takeoff 4.56 showed up in the market in NH. I am geared for 4.56 in the front and rear currently. But wouldn’t want to bother going any higher with the D44 axles since the gear teeth would be getting too small real quick. If that is the direction its heading, might as well get a D60 or bigger.

Blanket statements like this are a little misleading. Too small for what? For what driving? For what terrain? I say this as a guy with 5.13's who hasn't broke them yet.

 

[FreedomFur]

Blanket statements like this are a little misleading. Too small for what? For what driving? For what terrain? I say this as a guy with 5.13's who hasn't broke them yet.

Far enough! To clarify…

I do a lot of different Jeeping. I use it as my daily driver, it covers a lot of trails, and it rock crawls to the fullest capacity it is built for (it can’t keep up with Flex, Rocks, and Rollovers on YouTube). I have it built with a ProRock Dana44 fron’t with RCV shafts and factory Dana 44 rear. It is geared in 4.56 because it started as an Xtreme Recon. It has full belly skids and full MetalCloak 3.5” suspension system/lift.

I do not Jeep with other people 90% of the time. If I do, it is with one friend and only during the summer months when he has his TJ out on the road. Otherwise he is in the Jeep with me or its my wife. I have zero desire to be sitting in a park full of trails waiting my turn. There is a lot great terrain in NH that you can find.

That means if the R&P strips, the knuckles go, or something otherwise catastrophic, I am likely not getting out of there. I run the rig on 37s. And as much as I would LOVE 40s, I do not feel personally like I would want to take on the risk of failure by running them on D44 gears. I would want the much larger R&P provided by D60 axles or bigger.

There are a lot of different things that can go wrong out in the woods. My preference would be that it is something less catastrophic than a differential so that I have a higher chance of rigging it together and getting out.

The jeep will hopefully end up on 40s at some point, but that means new axles, hydro, drive shafts, etc before wheels and tires get added.

I hit a huge hole in a dirt road that was covered by snow last winter going about 10mph and it bounced the Jeep hard enough to bend the axle housing slightly. Freak accident. I was lucky it didn’t snap a tie rod end either and that it only bent one. It doesn’t take much to go wrong.

 

[Mx5red]

Blanket statements like this are a little misleading. Too small for what? For what driving? For what terrain? I say this as a guy with 5.13's who hasn't broke them yet.

I believe @wibornz runs 5.13s and has broken them twice

 

[fat_head]

I believe @wibornz runs 5.13s and has broken them twice

I just spent 30 minutes trying to find any information from him about it. Scrolled through 3000000000000 pictures of the exact same jeep lol jeez. I'd like to hear about his broken gears. Finding anything specific about/from him is impossible though.

 

[azwjowner]

I just spent 30 minutes trying to find any information from him about it. Scrolled through 3000000000000 pictures of the exact same jeep lol jeez. I'd like to hear about his broken gears. Finding anything specific about/from him is impossible though.

Somewhere he said that he thinks he has slightly bent his rear axle and that is causing his repeated gear failures, but I don't think he has had a chance to verify this yet.

 

[grimmjeeper]

I was thinking of watching to see if a takeoff 4.56 showed up in the market in NH. I am geared for 4.56 in the front and rear currently. But wouldn’t want to bother going any higher with the D44 axles since the gear teeth would be getting too small real quick. If that is the direction its heading, might as well get a D60 or bigger.

Just to clarify, the individual teeth don't get much smaller. You just end up with fewer teeth as the gear ratio goes up.

And to further clarify, no matter what ratio you have, there are only 3 or 4 teeth at most that are in contact with the ring gear at any one time. I took out some 2.73 gears from an old generation dana 44. 41 teeth on the ring gear but 15 on the pinion. The pinion head was huge but only 3 teeth were in solid contact. The 4.10 ratio has 41 teeth on the ring gear as well but only 10 on the pinion. And still only 3 teeth were in solid contact at any one time.

The teeth had a slightly different shape between the two ratios as you would expect from hypoid gears. But they were close enough to the same size that you couldn't tell which was which without using precision measuring tools.

 

[Mx5red]

Just to clarify, the individual teeth don't get much smaller. You just end up with fewer teeth as the gear ratio goes up.

And to further clarify, no matter what ratio you have, there are only 3 or 4 teeth at most that are in contact with the ring gear at any one time. I took out some 2.73 gears from an old generation dana 44. 41 teeth on the ring gear but 15 on the pinion. The pinion head was huge but only 3 teeth were in solid contact. The 4.10 ratio has 41 teeth on the ring gear as well but only 10 on the pinion. And still only 3 teeth were in solid contact at any one time.

The teeth had a slightly different shape between the two ratios as you would expect from hypoid gears. But they were close enough to the same size that you couldn't tell which was which without using precision measuring tools.

That’s interesting to hear, I thought it was fewer teeth engaged. I just hear people mention higher ratio when reasoning going to D60s and their bigger carrier/gears..
And in Wibornz post #68,492,801 he said he broke another set of gears (though he mentioned he wondered if his axle is bent).

 

[CarbonSteel]

Teeth engagement is not the issue or the reason that R&P's become broken--it is applying too high of a load to the R&P exceeding its capacity. The amount of pressure per square inch is too high when running large tires, excessive loads, wheeling in rocks, and poor load management when offroad.

The only way to reduce the load per square inch is to increase the overall diameter of the ring gear and that requires a larger axle. The diameter of the M220 axle ring gear is 8.6" which is smaller than axles found under Ford Mustangs (8.8"). The smallest ring gear that FCA should have used is 9.75" which is equivalent to axles found under Ford F-150 trucks.

Had they done that, we would not be hearing about R&P failures (not that we hear about that many anyway) because the axle would be up to the loading that some JLs see after modding.

 

[grimmjeeper]

That’s interesting to hear, I thought it was fewer teeth engaged. I just hear people mention higher ratio when reasoning going to D60s and their bigger carrier/gears..
And in Wibornz post #68,492,801 he said he broke another set of gears (though he mentioned he wondered if his axle is bent).

There's a lot of people going off bad information spread on the internet.

So... just like everything else...

 

[grimmjeeper]

Teeth engagement is not the issue or the reason that R&P's become broken--it is applying too high of a load to the R&P exceeding its capacity. The amount of pressure per square inch is too high when running large tires, excessive loads, wheeling in rocks, and poor load management when offroad.

The only way to reduce the load per square inch is to increase the overall diameter of the ring gear and that requires a larger axle. The diameter of the M220 axle ring gear is 8.6" which is smaller than axles found under Ford Mustangs (8.8"). The smallest ring gear that FCA should have used is 9.75" which is equivalent to axles found under Ford F-150 trucks.

Had they done that, we would not be hearing about R&P failures (not that we hear about that many anyway) because the axle would be up to the loading that some JLs see after modding.

Don't forget about deflection.

The thin wall casting of the differential housing isn't very strong. Add the stress of more power and bigger tires and the whole differential housing will flex. When that happens the gears are out of alignment and the stresses on the gear teeth are too much. So they break.

A more solid differential cover helps, as does a truss that welds to the housing.

Aftermarket housings have thicker walls and more external ribbing to add strength.

 

[CarbonSteel]

Don't forget about deflection.

The thin wall casting of the differential housing isn't very strong. Add the stress of more power and bigger tires and the whole differential housing will flex. When that happens the gears are out of alignment and the stresses on the gear teeth are too much. So they break.

A more solid differential cover helps, as does a truss that welds to the housing.

Aftermarket housings have thicker walls and more external ribbing to add strength.

All true, I added trusses and HD covers to mine to help compensate, but in the end, the axles are just undersized for the anticipated application and increased loads (e.g. not up to the mods that typical Jeepers do). Had FCA installed larger axles (9.75, 10.5, etc.) we would have less issues no matter what we throw at them.

 

[wibornz]

I just spent 30 minutes trying to find any information from him about it. Scrolled through 3000000000000 pictures of the exact same jeep lol jeez. I'd like to hear about his broken gears. Finding anything specific about/from him is impossible though.

I run heavy bead lock wheel on 37s.

The first pinion gear failed while I was pulling out of our camp spot up north in Michigan to go wheeling.

The second pinion gear failed while I was cruising in the desert, think flat smooth road. The Boarder Patrol will drive it at high speeds and it is very smooth. I could easily cruise it at 60+ mph smooth.

Because they failed during times of "normal" type of use and not during times of high load/high stress like a bind during rock climbing, I think that it is a gradual effect of long term use causing the failure.

It seam as though I get about 40,000 miles out of a set before they break. Mind you I put them through extreme use. I have towed our camper 48,000+ miles and the Jeep is off road for thousand and thousands of miles. It see many 16 hour days of driving and many 10 hour days off the road. The month of Jan, Feb, and March, we off roaded four to six days a week for the three months. We also rarely use a bypass on the trail.

I suspect that very few would put their Jeep through the type of use that my Jeep has seen. Think jumped it 5 feet in the air, water over the hood, deep mud, huge rocks, and so on for day, weeks, and months on end. With that said, I do have the philosophy of treat it like a race car, maintain it like a race car. It get oil changes, diff fluid changed and general maintenance very often. Tire rotations every 5,000 miles, suspension checks often with bolts checked for proper torque and so on.

So the Dana 44 is not just eating the rear pinion gear with 5.13. I have had the locker positioning sensor fail twice on the locker. I have had the magnetic ring in the locker fail twice also. I have bought two Dana 44 axles (new in the crate) to scavenge parts off it as they were not available to buy separately. Of course those locker parts failed each time a week or so before I was leaving on a month or two wheeling trip. So my only option was to buy the axle. I left December for a four to five month wheeling trip with a non functioning locker because I could not buy a 60 axle intake before I left and could not sensor replacement kit was backorder and would not come in before well left.

With talking to Dynatrac, they are under the assumption that I may have tweeted the axle just enough that it causes undue heat and stress causing the electronics to fail more often and to create addition stress on the gears when used under extreme loads. Think wheeling in Moab for 30+ days straight.

So in March, I had a new set of 5.13 gears installed, when I get home, I will replace the current Dana 44 axle with the one I have in a crate. That crate axle is missing the magnetic ring for the locker, but the sensor kits has came in to fix the locker, the crate axle will get truss added to it and it will get re-geared to 5.13 gears.

I just consider all of this as the cost of using the Jeep to off road thousand and thousand of miles.

 

[Joaquim]

Teeth engagement is not the issue or the reason that R&P's become broken--it is applying too high of a load to the R&P exceeding its capacity. The amount of pressure per square inch is too high when running large tires, excessive loads, wheeling in rocks, and poor load management when offroad.

The only way to reduce the load per square inch is to increase the overall diameter of the ring gear and that requires a larger axle. The diameter of the M220 axle ring gear is 8.6" which is smaller than axles found under Ford Mustangs (8.8"). The smallest ring gear that FCA should have used is 9.75" which is equivalent to axles found under Ford F-150 trucks.

Had they done that, we would not be hearing about R&P failures (not that we hear about that many anyway) because the axle would be up to the loading that some JLs see after modding.

Isn't m220 8.7 inch vs m200 8.5 inch?

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