A/T - 4L60-E/4L65-E New Pump/Seal/Case/Service
Bulletin No.: 04-07-30-023Date: May 12, 2004
INFORMATION
Subject:
Oil Pump Assembly Seal and Transmission Case Change
Models:
2002-2004 Cars and Light Duty Trucks
with 4L60-E or 4L65-E Automatic Transmissions (RPOs M30, M32 or M33)
An improved oil pump to case seal design has been made to the 4L60-E/4L65-E transmission. The new design affects the oil pump, the oil pump seal, the transmission pan bolts and the transmission case. The complete design was implemented in three phases.
The first phase, beginning in September 2002, relocated the machining of the oil pump 0-ring seal groove in the pump body. The 0-ring seal groove moved 1.6 mm (0.62 in) inward on the pump body in order to place the sealing surface deeper into the case bore. The relocated pump body groove can be identified by measuring the groove location. Pump bodies that measure 2.3 mm (0.09 in) from the machined surface to the groove opening have the relocated 0-ring seal groove. Pump bodies that measure 3.9 mm (0.15 in) are prior to September 2002 design.
The first phase also machined a case chamfer leading into the pump bore (2). The chamfer is designed to help eliminate possible 0-ring seal damage during pump installation.
Phase two modified the case casting and the chamfer into the pump bore. The casting change left additional material in the surrounding pump bore to allow deeper bore machining in order to create the necessary sealing surface for a new pump seal design. The leading surface into the pump bore was also machined with a modified chamfer (1).
Phase three will eliminate the oil pump body 0-ring seal groove and the 0-ring seal. Beginning March 2004, a new stamped carrier molded rubber seal (2) will be used to seal the pump assembly to the transmission case.
The pump sealing surface is now the outer diameter of the pump and the inner diameter (1) of the transmission case bore. Unlike the current 0-ring seal, which is installed on the oil pump body, the new seal is installed after the pump assembly is properly positioned and torqued in place. Seating the seal is accomplished when the torque converter housing is installed, which presses the seal (3) into position between the pump and the case bore (1).
As a result of the modified casting and the deeper pump bore machining, the area between the oil pan mounting surface and the pump bore has decreased. Because of the reduced material in this area (1) it is necessary to use the shorter oil pan attaching bolts (2). Early pan bolts (3), before November 2002, should not be used with the modified case design, since they are 1.0 mm (0.39 in) longer and could deform the chamfer surface (4).
Service Information
When Servicing transmissions with the new seal design, use the following precautions:
^ The outer diameter of the pump assembly and case bore must be clean and free of burrs or raised surfaces. Be aware of sharp edges that could damage the seal during installation.
^ The seal should be clean and dry before installation. It does not require lubrication for installation.
^ The seal should be inspected prior to installation for obvious damage.
^ It is preferable to hand-start the seal positioning the seal evenly around the case bore before installing the torque converter housing.
^ The seal can be easily removed by prying it out, typical of a pressed-on seal.
^ The seal may be reused, however a thorough inspection must be performed. Inspect the seal for the following conditions:
^ Distortion of the metal carrier or separation from the rubber seal.
^ A cut, deformed, or damaged seal.
^ Refer to the appropriate unit repair information in SI for seal removal and installation procedures.
Parts Interchangeability Information
In order to properly service the different designs, it is necessary to correctly identify and select corresponding parts for each level. This table provides a summary of the part usage for the different design levels.
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