K 2500 Truck 4WD V8-8.1L VIN G (2001)
Technical Service Bulletin # 03-07-30-031E
Date: 060130
A/T - Allison 1000, Leaks From Rear/Slips/Won't Engage
Bulletin No.: 03-07-30-031E
Date: January 30, 2006
TECHNICAL
Subject:
Allison(R) Transmission Leaks, Slips, Vehicle Will Not Move (Replace Rear Extension Housing, Change Torque Converter Relief Spring/Lube
Regulator Spring, Diagnose/Repair Driveline Imbalance)
Models:
2001-2003 Chevrolet Silverado 2500/3500 Series Pickup Models (4WD Only)
2001-2003 GMC Sierra 2500/3500 Series Pickup Models (4WD Only)
with Allison(R) 1000 Series Automatic Transmission (RPO M74)
Supercede:
This bulletin is being revised to update vehicle build dates. Please discard Corporate Bulletin Number 03-07-30-031D (Section 07 -
Transmission/Transaxle).
Condition
Some customers may comment that the transmission leaks from the rear, slips, or the vehicle may not move.
Cause
This condition may be the result of a cracked extension housing caused by a driveline imbalance. Driveline imbalance may be caused by any of the
following components. This is not an exhaustive list and other conditions that are not noted here may be found on vehicles.
^
Damaged or worn U-Joints (inspect both front and rear driveshafts).
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A front or rear driveshaft that is out of balance due to the following conditions:
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Foreign material stuck on the front or rear driveshaft (mud, concrete, tar, etc.). Nothing should be on the driveshaft. It must be clean.
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A damaged front or rear driveshaft (bent, dented, etc.).
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Foreign material that affects the motion of the U-Joints. All of the U-joints must be free to move within their full range of motion.
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Balance weights missing from a front or rear driveshaft.
^
For additional Items that affect driveline imbalance, refer to Corporate Bulletin Number 02-07-30-024B, Diagnosis of Cracked or Broken
Transmission Case, and the Vibration Diagnosis and Correction sub-section of SI.