{"nhtsa_id":634286,"type":"service_bulletin","type_name":"Service bulletin","date_added":"2002-09-28","date":"2002-06-01","document_id":"171K2K02","mfr_campaign":null,"replaces":null,"component":"POWER TRAIN:MANUAL TRANSMISSION","mfr_system":null,"summary":"SUBJECT PERTAINING TO MAIN REGULATOR VALVE MODIFICATION FOR IMPROVED COOLER FLOW AT IDLE AND TORQUE CONVERTER FRICTION PLATE CHANGES, MODEL 1000,2000,2400 AND 2000MH SERIES.*JB","document":null,"url":"https://open.wenmarpro.com/bulletins/634286","components":[{"id":"powertrain","name":"Transmission and driveline","parent":null},{"id":"manual-transmission","name":"Manual transmission","parent":"powertrain"}],"codes":[],"topics":[],"vehicles":[{"make":"GMC","model":"GM","year_from":null,"year_to":null,"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":[]}