NHTSA Engineering Analysis EA19004: Steering loss due to linkage separation
On December 17, 2018, NHTSA's Office of Defects Investigation (ODI) opened Preliminary Evaluation PE18016 to investigate alleged drag link failures in the steering system on model year (MY) 2015 and 2016 Ram 2500 trucks manufactured by FCA US, LLC (FCA). The drag link failures were found to be due to a safety defect with the steering linkage where the drag link adjustable connector (used to adjust the steering system), held in position by two opposing jam nuts, can loosen. The loosening of this part can lead to wear and deterioration of the threads and eventual separation of the drag link, causing loss of steering. During the course of PE18016, it was found that two styles of drag link were used by FCA on the subject vehicles. The subject vehicles consist of two drivetrain types including four-wheel drive (4WD) and two-wheel drive (2WD). The 4WD and 2WD trucks used drag links of differing design but both incorporated the same threaded connector. In January 2019 FCA issued recall 19V-021 to address a potential loss of steering control in certain Model Year (MY) 2013-2018 4WD RAM 2500 and 3500 trucks. The trucks using the 2WD style drag link were not included in the scope of recall 19V-021. ODI upgraded PE18016 to an Engineering Analysis EA19004 on December 12, 2019. The purpose of EA19004 was to investigate if the root cause of the safety defect addressed by recall 19V-201 also affected the 2WD trucks and evaluate FCA’s rationale for not including them. ODI also monitored incoming consumer complaints regarding the remedy associated with 19V-021 and evaluated the suitability and long-term effectiveness of the prescribed repair. In the Defect Information Report submitted for recall 19V-021, FCA stated that the outboard jam nut could loosen and result in damage to the threading of the steering drag link connector. This could cause a separation in the drag link resulting in a loss of steering control. FCA determined that only the 4WD style drag link was affect
US National Highway Traffic Safety Administration