C 3500 HD Truck 2WD V8-8.1L VIN G (2002)
Torque Converter: All Technical Service Bulletins
A/T - Allison 1000, Knocking Noise at Idle/Fluid Leaks
Bulletin No.: 03-07-30-038A
Date: October 18, 2005
TECHNICAL
Subject:
Allison Transmission Oil Leak, Abnormal Knocking Noise Heard at Idle (Diagnose and Repair as Required)
Models:
2001-2003 Chevrolet Silverado 2500/3500 Series Pickup Models
2001-2003 GMC Sierra 2500/3500 Series Pickup Models
with 8.1L Gas Engine (VIN G - RPO L18) and Allison(R) 1000 Series Automatic Transmission (RPO M74)
Supercede:
This bulletin is being revised to include new Warranty Labor Information. Please discard Corporate Bulletin Number 03-07-30-038 (Section 07 -
Transmission/Transaxle).
Condition
Some customers may comment on a transmission oil leak from the bottom of the converter housing, or a knocking type noise is heard with the engine
running.
Cause
The flywheel to converter mounting bolts may have worked loose from engine/road vibration. Use the diagnosis procedure given in this bulletin to
diagnose the vehicle for this potential cause.
Technician Diagnosis procedure
If the under vehicle inspection reveals transmission oil is leaking from the bottom of the converter housing to inspection cover interface, perform the
following diagnostic procedure.
For the diagnosis procedure, perform the steps indicated below.
1.
Disconnect the negative battery cable.
2.
Raise the vehicle.
3.
Remove the positive battery cable nut and cable from the starter.
4.
Remove the solenoid nut and wire from the starter.
