Drive Shaft

[shatto]

So, I'm watching the commercial for the new Tundra....You know, the one that is so strong, so tough, so much better.....

And there is the shot of the two-piece drive shaft, one of steel for strength, and the other of Aluminum to save weight.

And I think to myself; "Hmmmmm....."

My old Generation Numero Uno Tundra has exactly the set-up they say is new and better.

But my two part question is: why two sections and why two different metals?

[theholycow]

Apparently one piece vs. two piece is about length and durability. On another forum there is a thread about a one piece aluminum driveshaft that exploded at 130mph...now, granted, a pickup truck has no earthly reason to go that fast (and I posted such in that thread) but consensus was that a two piece steel shaft would have survived.

Also, doesn't a two piece shaft articulate at the joint? That would be an advantage for off-roading...

[shatto]

Some of those really long box-vans have 3 and 4 segment driveshafts.

I would guess it is easier to balance a short vs long shaft. They do rotate pretty fast.

[bobc455]

Originally Posted by shatto

But my two part question is: why two sections and why two different metals?

I agree that their claim makes no sense. If you have one "for strength", then you'd think it shouldn't be connected to a "weaker" shaft since the total driveshaft is only as strong as its weakest piece.

It's possible (although unlikely) that they are worried about critical speeds due to harmonics. Harmonics are a weird thing, they involve the weight & thickness of the shaft, the length, the material, and the balancing technique (and a few other things). If the rearend ratio is very short (i.e. 4.56) and the driveshaft speeds are WAY up there, and the driveshaft is very long (i.e. extended bed or something), this might be the issue.

On the other hand, it could be a way to get a better pinion angle, depending on how the truck geometry is set up.

-BC

[GasSavers_RoadWarrior]

Maybe it's something to do with not firing 6ft of solid steel harpoon at people when they crash.

[dkjones96]

4.30 rear ratio means that driveshaft hauls *** at speed. At 65mph it's turning 2930 rpm. That's a lot for a 6 ft driveshaft.

If there is a slip yoke at the carrier it's possible they used it to provide better durability at the transmission and transfer case. There are a lot of reasons to go with a two piece configuration. A lot of manufacturers have gone to it.

Two materials though? No idea. One can assume driveshafts are like chains. Only as strong as the weakest link.

[almightybmw]

No one's said it?
Clearance. It doesn't hang down as far, better drive over angles. I know most of you don't think about offroad, as that's not good for FE, but it's a damn truck. It has a ballsy V8 in it, that has crap for FE. You want good FE with a heavy truck, get a Cummins. Or a Duramax. But not a new one. The stupid UL Sulfur emissions junk makes for much worse mileage.

But, I would not consider a fullsize unless it was a diesel. In fact, I want to swap the Cummins B3.3T into my Sonoma. Same power is my 4.3, but 30+mpg.

Bah. Gas engines are a thing of the past.

[dkjones96]

Wouldn't the rear axle cause more ground clearance issues than the driveshaft?

[theholycow]

The rear axle moves up with the rear tires.

[dkjones96]

I guess some need to worry about that more than others. The skid plate for my gas tank is lower than the lowest point in my driveshaft. The front leaf spring shackle is about the same level as the differential input.