Three new recalls were issued by General Motors on Friday, bringing the total to a record 48 for the year.
More than 474,000 vehicles, mainly pickup trucks and SUVs from the 2014 and 2015 model years, have been recalled.
More than 50,000 were sold in Canada.
GM says a software glitch can cause the transmissions to shift into neutral on their own and if it happens when the vehicles are parked, they could roll away.
More than 20 million GM vehicles have been recalled worldwide so far this year.
The old record for recalls in a full year was 10.75 million vehicles, set by GM in 2004.