GM Drivetrain Tech Tip: Transfer Case Leaking Fluid – UnderhoodService

GM Drivetrain Tech Tip: Transfer Case Leaking Fluid

Fluid Leak at Left Hand Transfer Case Weep Hole or Between Transfer Case and Transmission (Replace Left Transfer Case Input Shaft Seal or Transfer Case O-Ring Seal). Models equipped with 6T45/70/75 Transmission RPO Codes MHC/MH4/MH6 for GM or AF33-5 AWD/PTU Automatic Transmission (RPO M45) for 2007-2008 Suzuki and Getrag 760 or 790 Power Takeoff Unit (Transfer Case).

Models:
2008-2010 Buick Enclave
2008-2009 Chevrolet Equinox Sport
2009-2010 Chevrolet Traverse
2010 Chevrolet Equinox
2007-2010 GMC Acadia
2010 GMC Terrain
2008-2009 Pontiac Torrent GXP
2007-2010 Saturn OUTLOOK
2008-2010 Saturn VUE

• Models equipped with 6T45/70/75 Transmission RPO Codes MHC/MH4/MH6 for GM or AF33-5 AWD/PTU Automatic Transmission (RPO M45) for 2007-2008 Suzuki and Getrag 760 or 790 Power Takeoff Unit (Transfer Case).

Some customer may comment on a fluid leak from the  transmission or transfer case area. Upon further diagnosis, the tech may find fluid leaking between the transmission and transfer case or from the left hand transfer case weep hole closest to the transmission.

First, thoroughly clean the area and use fluid dye to isolate the leak. It is critical to understand the location of the leak and the fluid type (i.e. ATF or transfer case gear lubricant). The transfer case left hand weep hole can leak both ATF and gear lubricant. If the leak is not coming from the transfer case weep hole, DO NOT replace the transfer case left hand input shaft seal.

Model 790 Transfer Case: Leaking from Left Hand Weep Hole

1. Remove the transfer case. Using published instructions and tools, the machined surface of the bore must be clean and free from scratches or nicks. Care must be taken not to scratch the seal bore when removing the old seal. To ensure proper alignment and depth of the seal, take four measurements every 90 degrees around the seal circumference, verifying uniform depth. The distance from the top face of the machined surface of the bore to the metal flange of the seal should be 24.3 +/- 0.1 mm (0.957 +/- 0.004 in). Failure to follow these instructions will result in seal failure.

2. Replace the left transfer case input shaft seal and the transfer case O-ring seal.

Leaking Between Transmission Case and Transfer Case

Replace the transfer case O-ring seal on the left output shaft.

Model 760 Transfer Case: Leaking from Left Hand Weep Hole

Remove the transfer case. Using published instructions and tools, the machined surface of the bore must be clean and free from scratches or nicks. Care must be taken not to scratch the seal bore when removing the old seal. To ensure proper seal alignment and depth, take four measurements every 90 degrees around the seal circumference. The distance from the top face of the machined surface to the metal flange of the seal should be 17.7 +/- 0.1 mm (0.697 +/- 0.004 in). Failure to follow these instructions will result in replacement seal failure.
Replace the left transfer case input shaft seal and the transfer case O-ring seal.

Leaking Between Transmission Case and Transfer Case
Replace the transfer case O-ring seal. Please follow this diagnostic or repair process thoroughly and complete each step.

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