[SBSerpent]

So this is what I did. Lifted the rear end so that both wheels were off the ground.
1) with the transmission in gear, I spun one wheel in one direction and the other wheel spun in the opposite direction
2) with the tranny out of gear, I spun one wheel and it did not affect the motion of the other wheel
3) with the tranny still out of gear, I spun the driveshaft by hand and both wheels spun in the same (forward) direction simultaneously

Took the car out for a drive today and I did feel both tires let loose a couple of times on hard acceleration.