K 3500 Truck 4WD V8-8.1L VIN G (2002)
Valve Body: All Technical Service Bulletins
A/T - Allison(R) Valve Body Revisions
Bulletin No.: 03-07-30-053
Date: October 24, 2003
INFORMATION
Subject:
Allison(R) Automatic Transmission Valve Body Hardware Changes
Models:
2001-2004 Chevrolet Silverado
2001-2004 GMC Sierra
with Allison(R) Automatic Transmission (RPO M74)
The valve body for the Allison(R) Series 1000 transmission has been revised for the 2004 model year to add modulated main pressure control. This
revision will provide additional transmission oil cooler flow and reduced pump load during certain low speed operating conditions. The revised
components will be installed on all 2004 transmissions and will be functional on the L18, 8.1 L gas engine and LLY, 6.6L diesel engine but not on the
LB7, 6.6L diesel engine.
Visible changes to the valve body assembly include an added modulated main valve body assembly, a control solenoid and a revised internal wiring
harness. The modulated main valve body and solenoid are located on the bottom, near the front of the valve body assembly and are connected to the
wiring harness by an additional wire and connector.
Important:
This revised valve body will be used to service all 2001-2004 models. The modulated main pressure components will not function on the 2001-2003
models as the TCM is not equipped with the calibrations necessary to make these components operate. Installation of a modulated main equipped
service valve body on a 2001-2003 transmission will not affect transmission operation.
Interchangeability
