Chevrolet Silverado 1999–2000 — technical service bulletin
Bulletin 020605003 · NHTSA communication 634770 · issued Jun 1, 2002
Technical service bulletin
communication type
Engine and Engine Cooling
component
1999–2000
model years
4
vehicle entries
Official summary
Exhaust moan or vibration at low vehicle speeds between 900-1200 rpm under load. *tt
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.