刚查了一下州里的规定是这样的

When selling your vehicle, accompany the purchaser of the vehicle to a secretary of state branch office to assure the title is transferred into your purchaser's name.  If you cannot do this, maintain a record of the sale for not less than 18 months.   A "record of the sale" can be either a photocopy of the reassigned title or a form or document that includes the year, make, vehicle identification number, name, address, driver license number, and signature of the person to whom the vehicle is sold and the purchase price and date of sale of the vehicle.  

Under Michigan law, a seller is not liable for any damages or a violation of law that subsequently results from the use of ownership of the vehicle by the purchaser if the owner maintains proof of sale as noted above.