The U.S. government's road safety agency is investigating complaints that the rear axles can lock up on some Dodge Ram pickup trucks, causing them to spin out of control.
The probe covers about 260,000 Ram 1500 trucks made by Chrysler from the 2005 model year.
The National Highway Traffic Safety Administration has 15 complaints from drivers that the rear differential locked or the drive shaft separated with little or no warning, according to documents posted on the NHTSA website Saturday. A differential is a device that allows the drive wheels to turn at different speeds.
Seven drivers reported the wheels locked up at speeds over 50 miles per hour. Two said the trucks went into a spin.
The drive shaft problem could be caused by loose nuts, according to the documents. No crashes or injuries have been reported.
In one complaint from February 2013, a driver told NHTSA he was on an interstate highway when the drive shaft disconnected and the truck began to spin.
"It was five seconds of terror that I thought would surely end in disaster," the driver wrote. When the truck stopped it was blocking an entrance ramp, and the driver had to drag it to the shoulder in speeding traffic, the complaint said. "I was lucky that I wasn't killed. Hopefully Chrysler fixes this fault before someone isn't so lucky."
Drivers who file complaints are not identified in NHTSA's database.
Investigations can lead to recalls, but so far none has been issued. A message was left Saturday seeking comment from a Chrysler spokesman.