Transmission Fluid Leak From Front of Transmission - Torque Converter Housing and Pump Area (Remove 2 Lower Torque Converter Housing Bolts, Add Copper Washers Under Bolts)

Some customers may comment on transmission fluid leaking from the front of the transmission. Diagnosis will indicate that the leak is coming from the torque converter housing and pump area.

Two possible leak points in the pump area may be the two lower converter housing to main housing bolts. There have been case porosity issues that can lead to fluid contacting the bolt threads and leaking out under the bolt head. Typically, porosity related leaks would begin at low mileage.

Remove the two lower torque converter housing bolts. Use the procedure listed below. If the bolt threads are wet with automatic transmission fluid (ATF) when removed, it is likely that the porosity condition exists. A copper washer, P/N 10139097, can be placed under each of the bolt heads to prevent future fluid leaks.

These washers were added to production transmissions beginning the week of September 8, 2003. If a transmission is being disassembled for service and copper washers are found under these bolt heads, it is important that they be reinstalled during assembly.

If the bolt threads are not wet with ATF when removed, the cause of the leak may be due to any of the ten converter housing oil pump retaining bolts being under-torqued or a damaged bolt seal. Refer to the Torque Converter Housing Bolt Seal Replacement procedure in the Service Manual (SI Document ID #697885).

Important: DO NOT replace the torque converter unless the following conditions exist:

Notice: The transmission must be in a vertical position (torque converter pointing up) whenever the torque converter is removed or installed. Removal or installation of the torque converter when the transmission is in a horizontal position is likely to cause a cut or damaged oil pump seal assembly, resulting in a leak.

1. Remove the torque converter from the transmission. Refer to the Torque Converter Replacement procedure in the Automatic Transmission -- Allison sub-section of the Service Manual (SI Document ID #702789).



2. Remove the two lower torque converter housing bolts (1).
3. Install the copper washer to each bolt and reinstall the bolts.

Tighten:
Tighten the torque converter housing bolts to 57 N·m (42 lb ft).

4. Install the torque converter into the transmission. Refer to the Torque Converter Replacement procedure in the Automatic Transmission -- Allison sub-section of the Service Manual (SI Document ID #702789).

Parts are currently available from GMSPO.

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*This is a unique labor operation number for use only with this bulletin. This number will not be published in the Labor Time Guide.