General Motors announced late Friday four more safety recalls covering more than half a million vehicles worldwide, including more than 57,000 in Canada.

It's the 48th recall the automaker has announced this year. More than 20 million vehicles have been targeted. That's more than the number of cars GM sold in the U.S. in all of 2013.

The biggest of Friday's recalls affects almost 467,000 four-wheel-drive Chevrolet Silverado and GMC Sierra pickups from the 2014 and 2015 model years, the 2015 Sierra Chevrolet Tahoe and Suburban, and the 2015 GMC Yukon and Yukon XL. More than 53,000 of the recalled vehicles were sold in Canada.

In these vehicles, GM says the transmission may electronically switch into neutral on its own. "If this occurs while a vehicle is in motion, no power will go to the wheels," says a GM release. The release goes on to say if the vehicle is stopped or parked, it may roll away if the parking brake is not set. The automaker says it knows of no crashes or injuries related to the issue.

Airbag problems in the Cruze

In the second largest recall, dealers have been instructed to replace the driver's side airbag inflator in more than 33,000 2013 and 2014 Chevrolet Cruze sedans. Just over 4,000 of the affected vehicles are in Canada.

GM says the driver's front airbag may rupture, sending metal pieces into the passenger compartment, or the airbag may not inflate in a crash. The company says it's aware of one injury related to this issue. Reuters says an airbag accident that left a Georgia woman blind in one eye led to the Cruze recall order.

The other two recalls are smaller:

  • Just over 2,000 2014 Chevrolet Corvettes (33 in Canada) are being recalled to replace faulty rear shock absorbers.
  • Almost 4,800 2013-2014 Chevrolet Caprice police cars and 2014 Chevrolet SS sport sedans are being called back to inspect possibly defective windshield wipers. The affected vehicles were all sold in the U.S. 

With files from The Associated Press and Reuters