Transmission General Information

WARNING: This page is about a different car, the 2004 GMC Sierra, 2004 GMC Cab & Chassis Sierra, 2004 Chevrolet Silverado, and 2004 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

When attempting to diagnose a suspected 1000 Series transmission problem, always begin by conducting the Functional Test Procedure. Refer to Functional Test Procedure (Diagnostic Information and Procedures) . This procedure indicates the proper path for diagnosing the transmission by making basic checks. This procedure will refer you to the locations of specific checks. After you have determined the cause of a condition, you either take corrective action or install a replacement transmission. Refer to Transmission Replacement (With 6.6L Engine) or Transmission Replacement (With 8.1L (L18) Engine) .

IMPORTANT: DO NOT, under any circumstances, attempt to diagnose a powertrain condition without basic knowledge of this powertrain. If you perform diagnostic procedures without this basic knowledge, you may incorrectly diagnose the condition or damage the powertrain components.

You must be familiar with some basic electronics in order to use this section of the manual. You should be able to use the following special tools:

A Digital Multimeter (DMM)
A circuit tester
Jumper wires or leads
A line pressure gauge set

The functional test procedures verify the correct operation of electronic components in the transmission. These procedures eliminate the unnecessary removal of transmission components.

IMPORTANT: If you probe a wire with a sharp instrument and do not properly seal the wire afterward, the wire corrodes and an open circuit results.

Diagnostic test probes are now available that allow you to probe individual wires without leaving the wire open to the environment. These probe devices are inexpensive, easy to install and they permanently seal the wire from corrosion.