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Service bulletin 21TR02

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.

The communication, as NHTSA indexes it (as of 2026-10-19)
TypeService bulletin
NHTSA id634297
Published by NHTSA2002-09-28
Manufacturer's number21TR02
Manufacturer's date2002-06-01
NHTSA componentPOWER TRAIN:MANUAL TRANSMISSION

NHTSA's summary

INFORMATION REGARDING SHIFT QUALITY CONCERNS WITH MECHANICAL MODULATORS OR REDUCED MODULATION MODIFCATION, MODEL 500 SERIES.*JB

The document

No address for NHTSA's copy can be built for this communication. Ask the dealer for it by the manufacturer's number.

Components

Transmission and driveline, Manual transmission

Vehicles listed
GMC GM

Listing a model year does not mean every vehicle of it is concerned: the document says which.