General Motors extended its record-breaking string of safety problems today with three more recalls, including a large one involving its top-selling vehicle.

The recalls, part of a top-to-bottom safety review, bring the company’s total for the year to 48, covering more than 20 million cars and trucks. That beats GM’s old full-year record of 10.75 million in 2004. Today’s recalls cover 474,000 vehicles worldwide for a variety of problems.

The largest affects almost 467,000 four-wheel-drive Chevrolet Silverado and GMC Sierra pickups, as well as GMC Yukon and Chevrolet Tahoe and Suburban SUVs. The Sierra is GM’s top-selling vehicle.

The company said a software glitch can cause the transmission transfer cases to shift into neutral on their own on 2014 and 2015 models.

That can cause loss of power, or it can let the trucks roll away if parked. GM says it knows of no crashes or injuries. The other recalls are much smaller and also had no reported injuries.