Drive line noise mystery? Solved

[Chamberpains]

When you measure the torsion bar length, be sure to measure the distance from where they mount on the frame to the axle. Not the whole length of the bar.

tor·sion
ˈtôrSHən/Submit
noun
the action of twisting or the state of being twisted, especially of one end of an object relative to the other.

Torsion bars hold the axle from moving left and right. But their main purpose is to control twisting of the axle.