One piece drive shaft vs 2 Piece
 

Anyone switch to a one piece drive shaft and notice any difference?
Mechanically it makes sense that it takes more power to turn than a aluminum shaft, but just trying to figure it if its worth
the cash.

They went with the 2-piece for a better pinion angle, and the shaft moves up and
down at the carrier bearing instead of the transmission tail shaft slip sleeve. This
means less movement, and no slip sleeve movement the transmission slip yoke. A
two piece shaft will also absorb some of the vibrations if it happens to go out of
alignment, due to dirt or getting bent.A two piece shaft is used to prevent the shaft
from bending at high RPM; this is know as the whipping effect. Thus, larger clearance
is required to accommodate a one piece shaft and its harmonics.

All in all, the S197s Mustang are fitted with a two-piece driveshaft, centered around reducing
harmonics. Ford wants you to enjoy a smooth ride. TWO PIECE:
https://cimg9.ibsrv.net/gimg/mustang...e2eaf68b67.jpg
See here, there is no forward or backward movement of the shaft. This also means
your tail shaft seal will last a lot longer.

https://cimg8.ibsrv.net/gimg/mustang...e59d073559.jpg
Your supposed to properly set up a one-piece driveshaft, all the experts agree that the engine and transmission should
be set in the chassis with the rear approximately 3 degrees below horizontal (a magnetic protractor can be used to check
this angle). In the rear, the angle of the rear end pinion will be set to 3 degrees above horizontal. When the car is finished
with all the weight added you should recheck the pinion angle. If any added weight has changed the pinion angle, correct
it. You would need an adjustable upper LCA to change the pinion angle. Angle setup for two-piece shafts is similar to the
one-piece. All three working angles should add up to zero.

I also read:
The Aluminum driveshaft is thicker than the stock two piece and even though it is lighter,
it will require the same amount of torque to turn since the amount of inertia on the aluminum
one piece piece is higher. Rotational torque is defined as the radius of the cross section,
multiplied by the moment of inertia times the angular acceleration. The moment of inertia is
larger on a hollow cylinder than it is on a solid piece, despite the difference in weight/mass.
The mass of a one piece shaft is concentrated further away from the center, requiring more
torque to turn. While on the solid two piece, the mass is concentrated in the center so less
torque is required to move it. This is like why larger wheels are harder to get moving/stop.
The one piece is also more likely to break or depart from the car, and ruin the underside of
the car; bend the floor pans, mess up the trans mount. People don't put on one of those
drive shaft safety loops, so it holds the shaft horizontal should it depart the vehicle. A one piece
can come right through the floor at 70, should it come off the yoke or flange, or break.

Anyhow, I don't think it's worth the cost for what you may or may not gain, especially for
3.8/4.0 V6 cars. Unless someone is almost giving one away, for $300 or less. The two
piece shaft is only 38 pounds.

Ford even makes a one piece for the S197s.

I also see the one piece has a rubber accordion section on the differential end. My guess is
this is where the shaft moves.

basically this is for peace of mind when your at the track. There have been a few guys that have had failures but not many. I switched mine out just so I didn't have to worry

Thanks so much for the input!
I got a lot more reading to do it seems. :) Got to separate marketing from facts.

My original driveshaft had a worn center bearing that would rumble at 95+mph. Since it's a non-serviceable part, my only option was to swap in an aluminum one-piece shaft. Being only half the weight is a definite advantage, and any harmonic is likely to occur at a speed well beyond what the car is capable of.

If you know how, you can replace the carrier bearing. There is a video on how
to replace that center carrier bearing assembly, however, 2-piece shafts are cheap,
and you may even be able to find the front shaft... Lots of GT people who have
converted, are selling their 2-piece, you can still use the front piece with the
carrier bearing from the same transmission type.

'IF' I had a Roush Stage 3 Mustang like you do, I would get an aluminum driveshaft. Hell, I have one on my 2011 v6 also with a safety loop :)

I have a "Two Piece" shaft from my 2014 car.......7K miles on it if anyone wants it.......free for pickup in SC or you can pay shipping!!:icon_cool:

Auto or Manual?

Also, there is a for sale section here. Though, right now, all you get are blank
pages...

Sorry......Manual!!