{"nhtsa_id":637387,"type":"service_bulletin","type_name":"Service bulletin","date_added":"2002-11-25","date":"2002-01-01","document_id":"41","mfr_campaign":null,"replaces":null,"component":"POWER TRAIN:MANUAL TRANSMISSION","mfr_system":null,"summary":"SOME VEHICLES EQUIPPED WITH THE ALLISON LCT1000 TRANSMISSION MAY EXPERIENCE A VERY HARSH 2-1 DOWNSHIFT AT A STOP OR ON THROTTLE REAPPLY. *TT","document":null,"url":"https://open.wenmarpro.com/bulletins/637387","components":[{"id":"powertrain","name":"Transmission and driveline","parent":null},{"id":"manual-transmission","name":"Manual transmission","parent":"powertrain"}],"codes":[],"topics":[],"vehicles":[{"make":"CHEVROLET","model":"SILVERADO","year_from":2001,"year_to":2002,"match":"exact","vehicle_ids":["2001_chevrolet_silverado","2002_chevrolet_silverado"]},{"make":"GMC","model":"SIERRA","year_from":2001,"year_to":2002,"match":"exact","vehicle_ids":["2001_gmc_sierra","2002_gmc_sierra"]}],"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":[]}