[Jac Mac]

Someting is moving in your suspension to make it do that, like a bush deflecting etc. Its 'normal' for some types of LSD, Traction Lok's etc to cause this to a certain degree, but if the problem is really bad then some part of the suspension needs a rethink. We call it torque steer where as you accelerate it requires a bit of input by you on the steering wheel to counteract ( possibly without realising ) and then when you lift off the two combine to make the reaction of deceleration & your countersteer so violent.