That is incorrect. Please research before you post info like that. What you say maybe true to something like a CRV but not RX350.
"The RX 350's all-wheel-drive system drops the previous solid center differential, which relied on the traction-control system to shift power between the front and rear wheels. In its place is a limited-slip viscous coupling device that Lexus says offers quicker response. Under normal situations, power is split 50-50 between front and rear wheels; if slippage occurs, additional power can be sent to the front or back."
