The South Carolina Department of Motor Vehicles has some good information. Here is some information about inherited vehicles from the DMV website that should point you in the right direction:
Inherited Vehicles
If you are a surviving owner of a car, and your name and the deceased’s name is separated by “or” on the title, you can sign as the sole owner for an auto title transfer.
If the names on the title were separated by “and“, or if there was only one owner on the title, distribution of the vehicle must be determined by the probate court.
Depending on the determined form of distribution, the court will issue one of the following:
- An Affidavit for Collection of Personal Property Pursuant to Small Estate Proceedings.
- Personal Representative with an original Certificate of Appointment.
- Probate Court Order.
To complete a South Carolina car title transfer, you will need one of the above documents, along with the title transfer form here: 400.
I usually tell my clients to go to the DMV with all of their paperwork – usually a death certificate and certificate of appointment. Most branches have someone up front to help direct people to the forms they need to fill out and where to go. If you are out of state, you can take care of it by mail, but it obviously will take a lot longer.
To get started with the small estate process (less than $25,000 worth of stuff but no real estate) here are the directions for the small estate affidavit: Small Estate Packet
If you qualify for the small estate, you will end up with an affidavit and order showing the DMV where everything should go.
In a full estate, the Personal Representative transfers the automobile using the form 400 above and the certificate of appointment. I have found it easiest to go go the DMV with the title, my certificate of appointment, and a death certificate.
If you can’t find the title, you can order one using the DMV form 400. If you are lucky, you may be able to get the new title and transfer it at the same time. (If there is a lien on the car, the lender usually has the original title.)
Palmetto Probate Blog 
This blog is dated 2016, but references “a signed Affidavit of Inheritance of a Vehicle (Form 4036).” Form 4036 has been obsolete since 2011.
Thanks for pointing that out! If I remember correctly, I had pretty much cut and pasted the information from the old website. I will update this ASAP. Thanks again!