Assembly and Component Identification

WARNING: This page is about a different car, the 2023 GMC Sierra 3500 HD and 2023 GMC Sierra 2500 HD. However, it is still accessible from the selected car via links, so may be relevant.

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Check the transfer case assembly bar code label (1) to determine if the assembly contains first or second design components. Refer to: Magna Transfer Case Bar Code Label and the Production Assembly Breakpoints Table.
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Separate the case halves. Refer to:Transfer Case Disassemble (with MYD)Transfer Case Disassemble (with MGM, MGU) .
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Removethe rear output shaft assembly (1) and the high/low clutch (2).
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Inspect the rear face of the input shaft. (LD)

A light duty assembly with first design components can be identified by an input shaft with 2 oil drain holes (1) 180 degrees apart.

A light duty assembly with second design components can be identified by an input shaft with 3 oil drain holes 120 degrees apart.
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Inspect the rear face of the input shaft. (HD)

A heavy duty assembly with first design components can be identified by an input shaft with 2 oil drain holes (1) 180 degrees apart.

A heavy duty assembly with second design components can be identified by an input shaft with 3 oil drain holes 120 degrees apart.
Refer to: Appropriate Parts Identification Table.