It represented a 32 percent rise from August, when hundreds of new Covid-19 cases were diagnosed, according to a report by the Vietnam Automobile Manufacturers Association (VAMA).
Passenger vehicles accounted for 75.7 percent of the sales, commercial vehicles for 23.5 percent and special-purpose vehicles for the rest.
However, sales in the first nine months fell 22 percent year-on-year to 179,155 units as social distancing was imposed in the second quarter due to the disease outbreak and incomes fell.
Local brand Truong Hai Auto (Thaco) retained the top spot with a 34.6 percent share of the market though its sales fell 11 percent to 59,709 units.
It was followed by Toyota with 41,109 units and Mitsubishi with 17,228 units, both representing double-digit declines too.
Honda and Ford rounded off the top five.
On June 28 the government cut first-time registration fees by half for locally made vehicles to foster sales amid the pandemic.
The reduction will last through this year before returning to old levels on January 1, 2021.
Auto sales had risen 11.7 percent to 322,322 units last year.