The National Highway Traffic Safety Administration opened a preliminary investigation last week into 2007-2008 model year Wranglers with automatic transmissions.

The government has received three complaints in the U.S. alleging overheating of the vehicle's transmission. One complaint said a fire occurred. Another said transmission fluid leaked onto the catalytic converter, leading to smoke.

Chrysler says it is aware of a small number of alleged fires in China involving the Wrangler but not aware of any U.S. cases. There have been no injuries and the automaker is working with regulators in the U.S. and China on the issue.

Vehicle investigations can lead to product recalls.