Quick answer: without probate, bring an affidavit of ownership by succession and supporting documents to the county treasurer; with probate, bring the representative's appointment papers instead.
A local office, not a centralized DMV
Full probate uses a different document set
If the estate is in probate, a representative or heir instead needs to gather the original vehicle title, their appointment papers, driver's license and Social Security information, disclosure statement form, and exemptions form, along with payment of transfer fees.
A lost title has its own fix
If the car title has been lost, stolen, or damaged, an Application for a Duplicate Certificate of Title must be filed, along with the duplicate title fee, in person at the local county treasurer or by mail.
A local probate attorney can review your estate — many offer a free consultation.
Every South Dakota county treasurer's office processes vehicle title transfers this same way, regardless of which county the decedent lived in.