{"nhtsa_id":635016,"type":"service_bulletin","type_name":"Service bulletin","date_added":"2002-10-16","date":"2002-06-01","document_id":"020730025","mfr_campaign":null,"replaces":null,"component":"POWER TRAIN:AUTOMATIC TRANSMISSION","mfr_system":null,"summary":"SUBJECT REGARDING HARSH SHIFTING, DELAYED UPSHIFTS, POSSIBLE CHECK TRANS LAMP ILLUMINATED, POSSIBLE DIAGNOSTIC TROUBLE CODE 21 STORED IN THE TRANSMISSION CONTROL MODULE (TCM) MEMORY. *TT","document":null,"url":"https://open.wenmarpro.com/bulletins/635016","components":[{"id":"powertrain","name":"Transmission and driveline","parent":null},{"id":"automatic-transmission","name":"Automatic transmission","parent":"powertrain"}],"codes":[],"topics":[],"vehicles":[{"make":"CHEVROLET","model":"W SERIES","year_from":1999,"year_to":2000,"match":null,"vehicle_ids":[]},{"make":"CHEVROLET","model":"W-SERIES","year_from":2001,"year_to":2003,"match":null,"vehicle_ids":[]},{"make":"GMC","model":"W SERIES","year_from":1999,"year_to":2000,"match":null,"vehicle_ids":[]},{"make":"GMC","model":"W-SERIES","year_from":2001,"year_to":2003,"match":null,"vehicle_ids":[]},{"make":"ISUZU","model":"NPR","year_from":1999,"year_to":1999,"match":"exact","vehicle_ids":["1999_isuzu_npr"]},{"make":"ISUZU","model":"NPR","year_from":2000,"year_to":2003,"match":null,"vehicle_ids":[]},{"make":"ISUZU","model":"NQR","year_from":1999,"year_to":2003,"match":"exact","vehicle_ids":["1999_isuzu_nqr","2000_isuzu_nqr","2001_isuzu_nqr","2002_isuzu_nqr","2003_isuzu_nqr"]}],"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":[]}