The aluminum is just for show we all know the cardboard does the structural work on these trucks that's why we can't keep driveshafts in them.

I had a local shop build a high speed balanced steel drivershaft with OE ujoints for my truck It was 450 and I've had it to well past 100 and shes smooth as glass.

 

I asked local dealer's service manager that question and he said for stability when its under flexation at higher rpms because the aluminum is so thin .. I thoight personnally it was to absorb vibrations but i dunno .. Maybe the techs know

Edit: just googled it lol : Figure 6-6).
To reduce the effects of vibrations and the resulting noises, manufacturers have used vari- ous methods to construct a drive shaft. An example of this is a drive shaft with cardboard liners inserted into the tube, which serve to decrease the shaft’s vibration by damping the vibrations.
Drive shaft performance has also been improved by placing biscuits between the drive shaft and the cardboard liner. These biscuits are simply rubber inserts that reduce noise transfer within the drive shaft.

 

NVH resistance

noise vibration harshness

AKA built outta **** materials

 

It goes tink like steel and sure don't look aluminum. I bought the truck used but from dealer and it was unmodified.



Edit: You can see in the first picture, there are tags of some sort at the end, 2 of them. Maybe there's some identifying information on them? I see them at both ends. I also see something similar on the 5" Driveshaft Specialties shown in post #6. Fairly certain it's not aluminum but now I'm curious if it is aftermarket

 

Stick a magnet to it

 

Looks like a steel one to me
Putting a magnet will def kno if its steel but its rusty like one

 

kc kid. they stop doin steel ds's well before the 07's came out. thats not a stock one.

tiff. pull the trans and check the case for cracks. when i lost my second ds i had to get a new case and a host of internal parts that were bent and burnt up. trans temp sky rocketed and burned up some stuff. just an fyi for ya. then again, mine put a hole in the bottom of the cab and put a hole in the flex pipe as well.

 

KC, post a pic of the tags if you can. That's def steel and looks near identical to my factory reg cab shaft. Some reg cabs and 4x4s will still use steel.

 

Didnt really enjoy that read lol, but thanks for the heads up and I will check it out

 

i thought mine would have been a simple tail shaft housing, out put shaft {yea, no idea where the hell it ran off too} and rear yoke. not so much. bent a lot of stuff in my trans when it narfed the ds.

better to get everything checked vs finding out the hard way.