4x4 driveshafts

[amorrison]

Fwd's that have different lengths of shafts from the differential to each of the wheels are designed with different shaft stiffnesses(ID,OD)per length to provide the same overall shaft stiffness.

Question

In 4X4's is the same idea applied to the driveshafts going from the transfer case to the front/rear differentials?

 

[Fabrico]

There should be no need to have that front-to-rear. I have not seen any 4WD or AWD that is designed to be truly locked together front-to-rear while on pavement. All have some sort of differential, viscous coupling, or the like.

 

[swall]

Amorrison4--my experience with interconnecting shafts for FWD is that torsional fatigue is the main design parameter. The weak point on a shaft is the spline and the spline size is set by the internal spline on the CV joint you are using on the vehicle. Since the same joint generally gets used on both sides of the car, the left and right side shafts will have the same weak point. Although sometimes extra material might be added to one shaft or the other, NVH would be a more typical reason.So, trying to make either the torsional or bending stiffness the same on each shaft would not accomplish much.