Service bulletin 020421005

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)
Type	Service bulletin
NHTSA id	634905
Published by NHTSA	2002-10-10
Manufacturer's number	020421005
Manufacturer's date	2002-06-01
NHTSA component	POWER TRAIN

NHTSA's summary

SOME VEHICLES WILL NOT MOVE WHEN 4-WHEEL DRIVE IS REQUESTED, NOISE, SHUDDER, POOR PERFORMANCE, TRANSMISSION / TRANSFER CASE SLIPS, TRANSMISSION WILL NOT UPSHIFT, SLIPS IN 4-WHEEL DRIVE. *TT

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

Vehicles listed
CADILLAC ESCALADE	1999, 2000
CHEVROLET AVALANCHE	2002
CHEVROLET BLAZER	1998, 1999, 2000, 2001, 2002
CHEVROLET S10	1998 to 2002
CHEVROLET SILVERADO	1998
CHEVROLET SILVERADO	1999, 2000, 2001, 2002
CHEVROLET SUBURBAN	1998, 1999, 2000, 2001, 2002
CHEVROLET TAHOE	1998, 1999, 2000, 2001, 2002
GMC JIMMY	1998 to 2002
GMC SIERRA	1998, 1999, 2000, 2001, 2002
GMC SONOMA	1998, 1999, 2000, 2001, 2002
GMC SUBURBAN	1998, 1999, 2000
GMC SUBURBAN	2001 to 2002
GMC YUKON	1998, 1999, 2000, 2001, 2002

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

Recalls for the same vehicles and component
05V005000	2005-01-07. POWER TRAIN:DRIVELINE:DRIVESHAFT

A recall listed here may apply to some of the same vehicles. Only the manufacturer can say whether it applies to one vehicle.

Other bulletins for the same vehicles and component
24-NA-141	2024-08-15. Service bulletin. GM is receiving damaged (cracked or broken) transmission cores returned to the reman facilities. The damage is being caused either in the removal process by the technician, or inadequate packaging or shipping. This bulletin advises the dealers to be more careful not to damage the transmissions during removal and to package the core properly for return.
PI1394B	2024-02-02. Service bulletin. This PI bulletin advises the technician on the proper way to install the pistons in an engine.
23-NA-153	2023-09-26. Service bulletin. The service bulletin advises the tech of a normal transmission shift condition and the delay in throttle response when the throttle plate is opened rapidly and advises the customer that it is normal for the delay.
PIP5640A	2022-10-17. Service bulletin. This Preliminary Information communication provides information to the technician to not remove the torque converter bolts and start the engine as this may cause damage to the torque converter of the crankshaft on vehicles equipped with an automatic transmission.
22-NA-181	2022-09-19. Service bulletin. This diagnostic tip advises the tech not to separate the flexplate from the torque convertor or damage my occur if the engine is started while diagnosing for noise from the engine or transmission.
PIP4379N	2018-10-15. Service bulletin. This Preliminary Information communication provides information to the technician about vehicles that have not engagement into drive, delayed, no engagement into reverse, and or a range inhibit. Technician may find Diagnostic Trouble Codes P0701, P0731, P0732, P0733, P0734, P0736, P0751, P0756, P0761, P0776, P0843, P0848, P0873, P0877, P0894 or P2723. Technician should follow published Service Information diagnostics for Diagnostic Trouble Code P0701 first. Technician will also ensure the fluid level is at the top of the hot band when the transmission fluid temperature is 175° Fahrenheit. Diagnostic Trouble Codes P0701, P0731, P0732, P0733, P0734, P0736, P0751, P0756, P0761, P0776, P0843, P0848, P0873, P0877, P0894 or P2723 can set by the following fluid service/filter change, transmission service involving removing the pan, low fluid level caused by leaks, or after long periods of storage. If the fluid level has been properly checked using the HOT check procedure listed in Service Information document 2408059 and any of the Diagnostic Trouble Codes reset during a cold start inspect the internal suction filter for possible cracks. If no other concerns are found inspect for a stuck lube regulator valve in the pump cover due to debris.
PIP3366C	2018-08-20. Service bulletin. This Preliminary information communicates to the dealer technician thatLight Duty Trucks equipped with automatic transmissions and 4 wheel drive may exhibit a condition of grinding/ratcheting type noise when shifting the automatic transmission into park while the transfer case is in 4 wheel drive low (4LO) range. Dealers technician's are advised this condition should be deemed a normal characteristic of 4WD low operation.
01-00-89-010J	2018-05-21. Service bulletin. This informational bulletin provides a revision for 01-00-89-010I to add the 2013 model year.
PIP5168F	2018-02-21. Service bulletin. This Preliminary Information communication provides information to the technician on the steps to diagnose and repair vehicles that may have a no crank concern. Technician will need to check the valve train for movement when the engine is cranked. If the valve train is not moving while the crankshaft is moving the front cover will need to be removed to inspect for a sheared cam sprocket locator pin. If the cam sprocket locator pin has sheared, replace the engine assembly. If the valve train is rotating during inspection, disconnect the Camshaft Position sensor and check if the engine will start. If the engine starts front cover will need to be removed to inspect for a sheared cam sprocket locator pin. If the cam sprocket locator pin has sheared, replace the engine assembly. If the engine does not start with the Camshaft Position sensor disconnected the follow published “Engine Cranks But Does Not Run” diagnosis in Service Information. Also perform an Engine Compression Test and Cylinder Leakage Test in Service Information documents all results. If the Service Information procedures above isolate an engine mechanical concern then removed to inspect for a sheared cam sprocket locator pin. If the cam sprocket locator pin has sheared, replace the engine assembly.
PIP4379M	2017-12-22. Service bulletin. This Preliminary Information communication provides information to the technician about vehicles that have not engagement into drive, delayed, no engagement into reverse, and or a range inhibit. Technician may find Diagnostic Trouble Codes P0701, P0731, P0732, P0733, P0734, P0736, P0751, P0756, P0761, P0776, P0843, P0848, P0873, P0877, P0894 or P2723. Technician should follow published Service Information diagnostics for Diagnostic Trouble Code P0701 first. Technician will also ensure the fluid level is at the top of the hot band when the transmission fluid temperature is 175° Fahrenheit. Diagnostic Trouble Codes P0701, P0731, P0732, P0733, P0734, P0736, P0751, P0756, P0761, P0776, P0843, P0848, P0873, P0877, P0894 or P2723 can set by the following fluid service/filter change, transmission service involving removing the pan, low fluid level caused by leaks, or after long periods of storage. If the fluid level has been properly checked using the HOT check procedure listed in Service Information document 2408059 and any of the Diagnostic Trouble Codes reset during a cold start inspect the internal suction filter for possible cracks. If no other concerns are found inspect for a stuck lube regulator valve in the pump cover due to debris.