 I just got my hyundai sonata serviced because it had this noise coming from the engine and it could be heard from the interior of the car.  It made noise when I shifted to drive and reverse. And was loud while driving on the highway.  I thought is was the power steering problem because it sounded like it when it is running low in fluid. However, that was not the case, but a solenoid problem.  The parts has to be ordered and will call when it arrives. Hopefully, that would fix the problem.  If not, according to the service staff, the transmission would have to be replaced. VERY SAD! I had the vehicle for 2 years and put 44,000 miles on it already with regular maintenance.  We like to travel!