Fiat said in documents that if the tailgates open, unsecured cargo could fall into the road and cause an accident.
Models affected by the recall include Ram 1500, 2500 and 3500 pickups from model years 2015 through 2017.
Although Fiat says no crashes or injuries have been linked to the problem, the automaker says it has received more than 5,800 complaints and warranty claims about the tailgate issue.
Dealerships will fix the tailgate at no cost to truck owners. The recall is scheduled to begin on September 14.