Is it legal for a current buyer sell the rights of his automobile without contacting the lender?
If the lender still has a lien on the vehicle, they are co-owner (and in a legal sense, probably full owner) of the vehicle. If your question is can you sell the vehicle to another owner, the answer is no – you are not the holder of the title, and the new owner will need the title transferred to be the rightfull owner of the vehicle. Once your car is fully paid off, the lender will send you the title to your vehicle, and release the lien they have on the asset. Then the car is yours to do whatever you wish with it.