BMW E46 318d Auto / 320i Manual with 188L Casing / 323i Auto / 325i / 325ti / 325xi / 328i 3.46:1 ratio / 330i Auto. The helical gearing manages the distribution of friction within the LSD. When torque is applied to the helical gear system it creates force that pushes the gear into the differential body, thus creating friction.
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