General Motors extended its record-breaking string of safety problems, announcing Friday 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.

Friday’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. Most were sold in the U.S. and Canada, with a small number of exports. Dealers will recalibrate the software.

The other recalls are much smaller and also had no reported injuries. One affects nearly 4,800 Chevrolet SS and Caprice police cars with faulty windshield wiper modules. Gear teeth can become stripped, causing the wipers to fail. Dealers will replace modules if needed.

In the other case, dealers will replace the two rear shock absorbers in about 2,000 2014 model year Chevrolet Corvettes with the FE1 or FE3 suspensions. An insufficient weld could lead to a fracture.

GM’s safety troubles, coupled with some large recalls from other manufacturers, have pushed the U.S. auto industry to a new full-year record for the number of vehicles recalled. Automakers have recalled 32.4 million vehicles in less than six months, surpassing the old annual record of 30.8 million, also set in 2004, according to Stericycle, a firm that tracks recalls and helps corporations manage them.

GM’s troubles started in February when it began recalling older small cars to fix ignition switches that can turn off engines on their own. That kills power steering and brakes and can cause drivers to lose control. It also disables the air bags. The problem ballooned to 2.6 million vehicles, and GM was forced to admit that it knew of the defect for more than a decade yet didn’t recall the cars until this year. GM says the problem caused 54 crashes and at least 13 deaths, although lawmakers say the death toll is closer to 100.

The ignition switch problem touched off a massive safety review in the company, as well as investigations by Congress, the Justice Department and the National Highway Traffic Safety Administration. GM paid NHTSA a $35 million fine for delays in reporting problems to the safety agency, and it has announced or taken charges totaling $2 billion to cover recall costs.

On Thursday, NHTSA posted documents showing that GM would recall about 29,000 Chevy Cruze compacts in the U.S. for an air bag problem. GM said Friday that 4,000 Cruzes from Canada are included in the recall.

(AP)