After experiencing a shudder/shake while driving the Pathfinder around 40 mph, we took it in for repair. The shop discovered that the radiator was leaking coolant into the transmission. Best case scenario, we replace the radiator and flush the transmission/service for $1200. Worst case scenario our transmission is damaged beyond repair and that's a $4000 fix. Checking online this is a known issue for Nissans of this type and class action lawsuit resulted from it, but no recall of the defective radiator.