Quick answer: use Form MVT-22 (Affidavit of Surviving Spouse or Rep), with the exact requirements depending on whether a spouse, an heir, or a joint owner is claiming the vehicle.
A surviving spouse pays no title fee
An heir needs more documentation, and a fee
An heir, when no personal representative has been appointed, needs a title application, the vehicle title, a notarized MVT-22 signed by all immediate heirs, a statement from the probate court showing no will has been probated, and a transfer of ownership — plus a $33 fee.
A joint owner skips this process entirely
Under joint ownership, when a joint owner dies, the surviving owner retains complete ownership of the vehicle automatically — no MVT-22 or title fee is needed for that transfer specifically.
A buyer from a full estate needs the PR's own paperwork
A person purchasing a vehicle from an estate with an appointed personal representative must obtain the title transferred by that personal representative, along with a copy of the PR's appointment from the Probate Court.
A local probate attorney can review your estate — many offer a free consultation.
The Maine Bureau of Motor Vehicles processes MVT-22 the same way statewide, regardless of which county's Probate Court would otherwise handle a formal estate.