A seat track system for a seat of a vehicle includes at least one seat track having a lower track member adapted to be fixed to a vehicle structure and an upper track member adapted to be connected to a seat and moveable relative to the lower track member. The seat track system also includes a manual positive engagement locking system cooperating with the at least one seat track to allow longitudinal adjustment of the upper track member relative to the lower track member and to positively engage the at least one seat track such that a locking element does extend through the locking plate but does not extend below the lower track member.