{"nhtsa_id":10083621,"type":"service_bulletin","type_name":"Service bulletin","date_added":"2016-10-27","date":"2016-01-29","document_id":"FSB 593-013A","mfr_campaign":null,"replaces":null,"component":"POWER TRAIN","mfr_system":null,"summary":"GRADE GRIPPER SOLENOID, REPLACEMENT. ON SOME MACK CHU, CXU, GU, AND TD TRUCK MODELS BUILT BETWEEN 04/31/2008 AND 11/30/2015, THE SOLENOID VALVE FOR THE GRADE GRIPPER FEATURE IS PRONE TO INTERNAL CONTAMINATION IN HARSH ENVIRONMENTS. THE INTERNAL CONTAMINATION OF THE SOLENOID VALVE IS CAUSED BY THE BUILDUP OF GRIME, SALT, ROAD DEBRIS AND OTHER SOLID CONTAMINANTS. IN SOME CASES, THE BUILDUP OF SOLID CONTAMINANTS CAUSED THE SOLENOID VALVE TO MALFUNCTION. A SIMILAR MALFUNCTION IS POSSIBLE IF THE SOLENOID VALVE IS EQUIPPED WITH A VENT FITTING THAT FREEZES OVER. THE MALFUNCTION CAUSES THE TRAILER BRAKE CIRCUIT TO MAINTAIN TRAILER BRAKE PRESSURE AFTER A GRADE GRIPPER EVENT.","document":null,"url":"https://open.wenmarpro.com/bulletins/10083621","components":[{"id":"powertrain","name":"Transmission and driveline","parent":null}],"codes":[],"topics":[],"vehicles":[{"make":"MACK","model":"CHU","year_from":2009,"year_to":2016,"match":null,"vehicle_ids":[]},{"make":"MACK","model":"CXU","year_from":2009,"year_to":2016,"match":null,"vehicle_ids":[]},{"make":"MACK","model":"GU","year_from":2009,"year_to":2016,"match":null,"vehicle_ids":[]},{"make":"MACK","model":"TD","year_from":2009,"year_to":2016,"match":null,"vehicle_ids":[]}],"as_of":"2026-10-19","note":"A bulletin is a manufacturer's communication to its dealers, as NHTSA indexes it. The summary is NHTSA's. The document is the manufacturer's: read it at NHTSA. A bulletin is not a recall, and listing a model year does not mean every vehicle of it is concerned.","attribution":[]}