Chevrolet Avalanche 2003 — technical service bulletin
Bulletin 01637 · NHTSA communication 10007653 · issued Jan 1, 2004
Technical service bulletin
communication type
Electrical System
component
2003
model years
6
vehicle entries
Official summary
Transfer case inoperative or shifts to 4lo after encoder motor sensor replacement. *mj
Vehicles covered
What a TSB means. Technical service bulletins are repair guidance manufacturers send to dealers — they are not recalls, and repairs are not automatically free (warranty extensions are an exception worth checking). The full document is available via NHTSA’s vehicle lookup.