Aluminum Driveshaft failures?

[TommyDuncan]

I noticed how large the stock driveshaft is on my 18. Has anyone destroyed one in the rocks yet? I haven't seen anything on here about replacing it, but it looks vulnerable.

A good friend told me it should be the first thing to go, but he plays in the rocks for a living. There are other things I would like to spend money on first.

I'm also practically walking distance from Adam's Driveshaft so if I get one I will show and tell...

[1pieceatatime]

At least one destroyed on the rocks at PWIM a few weeks back. A couple of others got some nice battle scars.

[Low_Sky]

Yes, they do get destroyed. My local driveline shop told me that the shaft length on my 2015 was too long for steel, there would be balancing/vibration problems at high speed. Given that I intend to regear to 5.13 at some point in the future (even higher driveshaft RPMs), and drive at highway speed more than I’m on rocky trails that eat driveshafts, I’ve decided to just trust them for now.
The shafts on the 2013 and earlier 5.7 Hemi PWs are shorter (not sure if it’s enough to really make a difference) and I know at least one member here is using a steel shaft on one.


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[KevinABQ]

At least one destroyed on the rocks at PWIM a few weeks back. A couple of others got some nice battle scars.

There were 3 that failed at PWIM last I knew. Two rear and one front. The front one seemed to just have a catastrophic u-joint failure, the shaft might have been ok. The rear ones were cut in half.

One of the rear ones was the Key’s, not sure who the other was.

[DamageWagon]

Yes, they do get destroyed. My local driveline shop told me that the shaft length on my 2015 was too long for steel, there would be balancing/vibration problems at high speed. Given that I intend to regear to 5.13 at some point in the future (even higher driveshaft RPMs), and drive at highway speed more than I’m on rocky trails that eat driveshafts, I’ve decided to just trust them for now.
The shafts on the 2013 and earlier 5.7 Hemi PWs are shorter (not sure if it’s enough to really make a difference) and I know at least one member here is using a steel shaft on one.


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It’s actually the other way round, the 13-present shafts are 2” shorter than the 10-12 shafts. The 03-09 shafts are much shorter though.

I couldn’t find local shops able to do the length of driveshaft we have. Tom Woods ended up being able to do a steel shaft in that length but they only do steel. Mine vibrates a liiiittle but more than stock but it isn’t annoying.

[OffroadTreks]

I noticed how large the stock driveshaft is on my 18. Has anyone destroyed one in the rocks yet? I haven't seen anything on here about replacing it, but it looks vulnerable.

A good friend told me it should be the first thing to go, but he plays in the rocks for a living. There are other things I would like to spend money on first.

I'm also practically walking distance from Adam's Driveshaft so if I get one I will show and tell...

Yeah, they explode instantly when they make contact with a rock. They are as thin as an aluminum can. I'm not joking.

It's not really the first thing you need to replace. Just don't use your drive shaft as a rock slider and you'll be fine. You want ramps. Not ledges with undercuts. That will get you every time.

[KevinABQ]

Yeah, they explode instantly when they make contact with a rock. They are as thin as an aluminum can. I'm not joking.

It's not really the first thing you need to replace. Just don't use your drive shaft as a rock slider and you'll be fine. You want ramps. Not ledges with undercuts. That will get you every time.

Well, not always ‘instantly’. I scratched the hell out of mine in 2018 and it’s still working today. But I noticed there sure was a lot more warnings about what not to do this year, and nobody lost a rear drive shaft after those first two.

I’ll also say that is Chris didn’t haul around a spare rear drive shaft in his truck the week would have sucked for a couple of people.

I’ve got to start thinking about what spares to have handy.

[Low_Sky]

Yes, they do get destroyed. My local driveline shop told me that the shaft length on my 2015 was too long for steel, there would be balancing/vibration problems at high speed. Given that I intend to regear to 5.13 at some point in the future (even higher driveshaft RPMs), and drive at highway speed more than I’m on rocky trails that eat driveshafts, I’ve decided to just trust them for now.
The shafts on the 2013 and earlier 5.7 Hemi PWs are shorter (not sure if it’s enough to really make a difference) and I know at least one member here is using a steel shaft on one.


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It’s actually the other way round, the 13-present shafts are 2” shorter than the 10-12 shafts. The 03-09 shafts are much shorter though.

I couldn’t find local shops able to do the length of driveshaft we have. Tom Woods ended up being able to do a steel shaft in that length but they only do steel. Mine vibrates a liiiittle but more than stock but it isn’t annoying.

I'm a dirty liar. Thanks Marcus!

[Colibri]

There’s a shop local to me that does heavy duty aluminum shafts, it dwarfs the oem one in my truck. Much much stronger and thicker higher quality material. Pics in my build thread somewhere.

Personally I prefer the shaft to be the sacrificial part in the rear driveline equation, that’s much easier to deal with than a damaged transfer case or pinion. A big steel shaft that gets bent will destroy other drivetrain parts in very short order.

I run a driveshaft containment hoop up front, because that letting go will cause tremendous damage. Out back I haven’t bothered yet but will likely run tabs for a limit strap style containment loop

[KevinABQ]

There is a huge range of hardness and strength of aluminum alloys. I don't know what alloy they use or why they chose it, but I'd bet that "resists sharp rocks" wasn't a big part of the selection criteria.

Several people at PWIM had thoughts on how to protect the drive shaft, but we'll see if these translate into products. It looks like a fairly hard task to do it effectively without adding a lot of weight.

[trk4sale]

I changed mine out to steel after I noticed a small dent in the stock aluminium shaft. I was thinking about how you can stand on a empty beer can, but as soon as you dent the side, catastrophic failure!

[TommyDuncan]

I talked to Adam's.
There is a chart and they aren't legally allowed to build a steel shaft over 72" for highway use. They can build a thicker walled aluminum or build a 2 piece steel shaft with double cardans. He also said either would be expensive.
I got the impression he will build whatever I want as long as it is for my pto driven rotisserie bbq and I would have to sign a waver.

I am now wondering about a single traction bar mounted to the frame with a shackle that doubles as a driveshaft guard. That would also eliminate that kicker shock contraption. I've seen it done on leaf spring vehicles but never anything like this.

[TankerZak]

Sounds illegal to build one not illegal to have/use one. I'd just go to someone else...

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[OffroadTreks]

Mine is 66 inches.

[DamageWagon]

What’s with everyone thinking a steel shaft is going to turn into a pool noodle and make their truck explode? If you hit it in the rocks you’re probably going to slide off something. The likelihood of you dropping the entire rear weight of the truck perfectly on the shaft and blowing up the transfer case is pretty minimal. The pinion is a more likely hazard but I imagine it can take some good load.

If you bend your steel shaft it should be pretty minimal. If it’s to the point of vibrating to death ITS GOING TO TELL YOU

[TommyDuncan]

Mine is 66 inches.

Thanks. Measuring mine was next on my list...
I think he said 72"... I will double check.

[TommyDuncan]

What’s with everyone thinking a steel shaft is going to turn into a pool noodle and make their truck explode? If you hit it in the rocks you’re probably going to slide off something. The likelihood of you dropping the entire rear weight of the truck perfectly on the shaft and blowing up the transfer case is pretty minimal. The pinion is a more likely hazard but I imagine it can take some good load.

If you bend your steel shaft it should be pretty minimal. If it’s to the point of vibrating to death ITS GOING TO TELL YOU

James Adam's explained that it is twisting stress that is the problem. Diameter is the solution but steel would get really heavy fast. I think the chart was based on length and the size of the U-joint, which would determine load on any OEM application.

[DamageWagon]

Factory shaft on my 11 was 4.5”x.080”. My steel shaft is 4”x.080” (if I remember right). Our trucks don’t make enough torque to trash that size shaft. 3500 Cummins pushing 1000ftlb is a different animal

[Colibri]

It’s all about end use I think. I stuck with Aluminium because I likes the go fast and don’t want a heavier driveshaft. If I were a Moab guy like mikekey I’d probably have steel. If I went steel I’d also install the slip yoke eliminator I have sitting on the shelf. Options are good.

Rear driveshafts are relatively harmless compared to our fronts I think. I’ve known several guys that had a front shaft let loose at the double cardan and beat the shit out of the truck. Thousands of dollars in repairs. A broken ujoint or some other catastrophic failure out back and I’d rather have an aluminum shaft flailing around than a steel one, but Marcus is absolutely right, these driveshafts were built with diesel weight and torque in mind and breaking one with a gasser would be for the record books lol

[OffroadTreks]

The thing about the rocks is that it's literally an aluminum can. It doesn't take much. If you contact a rock and it spins, it slices open.



We have a lot of articulation in the back and the drive shaft gets exposed easily.

[Low_Sky]

The thing about the rocks is that it's literally an aluminum can. It doesn't take much. If you contact a rock and it spins, it slices open.



We have a lot of articulation in the back and the drive shaft gets exposed easily.

Looks like that shaft went for a pretty good ride on that rock before it let go.

And I hope you’re not hitting rocks with the axle at full airborne droop.

Our aluminum shafts aren’t as strong as a well designed steel shaft would be, but they’re not the fragile little butterflies you’re making them out to be either.


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[OffroadTreks]

they’re not the fragile little butterflies you’re making them out to be either.

They are.

There was no spinning tires involved. I was just on it. And backing off didn't help. It let go. We've seen this multiple times now. If the drive shaft is on a rock and it spins, it will cut it open in a heartbeat.

My wife barely tapped our spare a day later on Hells leading a group and that driveshaft developed a vibration from being thrown out of balance. The reality is, they are incredibly fragile.

If you want to drive over rocks, bring a spare or get a steel shaft.

[DamageWagon]

When I cut my driveshaft on a ledge I didn’t even feel it. Truck stopped moving forward and I could hear the tube flinging. I checked a guy’s truck that had just rubbed a rock and the mark brushed off by hand, he barely got it. But most of the time if the rock is tall enough to intersect the shaft, the shaft will be gone. They really don’t take any load and they tear very easily once damage begins.

All of this said, some guys here have mentioned preemptively getting a driveshaft done, and I just wouldn’t do that. It isn’t an upgrade item except by necessity in my opinion. I’ve had the truck buried to the frame in a silt bed with the stock shaft leaving a nice deep impression in the ground and it was fine.

[OffroadTreks]

All of this said, some guys here have mentioned preemptively getting a driveshaft done, and I just wouldn’t do that. It isn’t an upgrade item except by necessity in my opinion. I’ve had the truck buried to the frame in a silt bed with the stock shaft leaving a nice deep impression in the ground and it was fine.

I'd agree. Steel is really if you expect to be trying harder lines. Most of it can be avoided by taking your time and staying off harder lines. But accidents do happen. A spare shaft might be a good idea.

Also, when you have a spare, don't leave it at home, lolol

[DamageWagon]

A few years ago I think we were all much less prepared in Moab and nobody was breaking anything. We were going much slower with a lot more spotting. Now everyone has 37’s and we go 2-3x as fast on trails and we break stuff.

I suggest carrying a spare spotter.