'05: why the 2 piece driveshaft?

The reason for the two is is probably to do with the new longer wheelbase. When the lenght of the drive shaft gets longer the is a lot of weakness in such a long drive shaft. And it may have alot to due with angularity it brings the rear suspension and drive line archs closer to the same . I'll will also reduce some vibration. Example short wheelbase trucks have a single drive shaft longer wheelbase have two piece. they also reduce a drive line bump on enitial acceleration, anyone whos owned a 96-2000 tahoe knows what I am talking about. But this is just a guess why they may have used it reliablity and reduced harmonics.

The primary reason for a 2 piece driveshaft is to reduce vibration.

Somewhere I read that the V6 has a 1 piece driveshaft and the GT a 2 piece.

2 piece driveshaft

I have a thunderbird and this issure hits home. A tbird with a longer wheel base it is very easy to get driveline vibration. In a tbird it is usualy around 70 mph. The way this is fixed is to use a high quaility dennies or dennis reinheart allumnim drive shaft. This is another reason. A driveshaft has a critical speed Imagine spining a piece of string the faster it spins the more it whips and it dose it to much it can break the tailshaft. The shorter driveshaft has a much higher critical speed. There is several articles over on tccoa.com.

makes perfect sense...they should just go carbon and reduce the inertia too...what, thats cheap

did they change the wheel base much? or has this been a problem on the current mustangs too?

Another reason would be to reduce unsprung weight, at the cost of slight angulation increase. thats why it would be on the GT, a stiffer suspension would keep the axle from moving, so you souldnt get as much angulation anyways, and the unsprung weight difference would benefit the performance targeted car rather than the ****ty v6

A long time ago I read some info. as to why Ford put a 2 piece driveshaft on the Lincoln LS. Originally Ford planned to sell the Lincoln LS in Europe. The LS was designed to cruise all day long at 120+ MPH (ie. Autobahn) and has a top speed of over 140 MPH. A single piece driveshaft had too much vibration at those speeds so they went to the 2 piece unit.

Since the LS has IRS, the driveshaft does not affect the unsprung weight, but as someone posted above, I suppose it could make a difference on a live axle car.