The expansion covers certain Ram 1500, 2500 and 3500 pickups from the 2013 through 2018 model years that have power locking tailgates. Affected 2015 through 2017 trucks have 8-foot beds, and the affected 2013, 2014 and 2018 trucks have beds of other sizes and were built before April 1, 2018.
Fiat Chrysler says it's not aware of any injuries or accidents caused by the problem.
The company recalled about 1.1 million trucks in the U.S. in 2018 for the same problem, and added 410,000 in May of 2019, for a total of more than 2.4 million. Most of the recalled trucks are in the U.S. and Canada.
A tailgate tab can fracture and cause the tailgates to unlatch, increasing the risk of cargo spilling onto the road.
Fiat Chrysler says the recall expansions came because of reviews of customer data as it monitors vehicles in the field. The company says that all loose cargo in the bed should be secured before driving.