K 2500 Truck 4WD V8-5.3L VIN T (1999)
PROM - Programmable Read Only Memory: All Technical Service Bulletins
Driveline - Vibration/Growl Noise
File In Section: 07 - Transmission/Transaxle
Bulletin No.: 99-07-30-010A
Date: June, 1999
TECHNICAL
Subject:
Driveline Vibration/Growl Noise (Reprogram PCM)
Models:
1999 Chevrolet and GMC C/K Models (Silverado and Sierra) with 4.8 L or 5.3 L Engine (VINs V, T - RPOs LR4, LM7) and Hydra-Matic 4L60-E
Transmission (RPO M30)
This bulletin is being revised to clarify the correction information. Please discard Corporate Bulletin Number 99-07-30-10 (Section 07 -
Transmission/Transaxle)
Condition
Some customers may comment about a driveline vibration/growl noise at speeds between 56-80 km/h (35-50 mph) with low engine speeds.
Cause
Engine torsional vibration when the torque convertor clutch is engaged at low engine speeds, 1100-1400 RPM, can excite various driveline components.
These driveline disturbances can cause noises and vibrations that the driver may feel and/or hear.
Correction
Reprogram the Powertrain Control Module (PCM) with the calibrations listed in this bulletin. The calibration will change the minimum torque convertor
clutch engagement speed to 1500 RPM. These calibrations will have all of the latest production improvements, including the improvements in Corporate
Bulletin Number 99-07-30-009 detailing harsh 1-2 and 3-2 shifts.
Parts Information
The calibrations listed are electronic calibrations and are NOT available from GMSPO. Calibrations will be available from Techline starting April 1999,
on the 1999 Disk 10 CD ROM.
Warranty information
For vehicles repaired under warranty, use:
Labor
Operation
Labor Description
Labor Time
PROM
Use Published
J5355
Reprogramming
Labor Time
