DETROIT (AP) — U.S. safety regulators are investigating complaints that rear axles can lock up on some Dodge Ram pickup trucks, causing them to spin out of control.

The National Highway Traffic Safety Administration says the probe covers about 260,000 Ram 1500 trucks made by Chrysler from the 2005 model year. The agency has 15 complaints from drivers that the rear differential locked or the drive shaft separated with little or no warning.