THM 4L60-E - Intermittent Pressure Rise On 1996 Models Only

COMPLAINT: Beginning at the start of production for all 1996 model vehicles equipped with the THM 4L60-E transmission, there was a VCM (Vehicle Control Module) installed on the vehicles with an internal ground wire that connects the two printed circuit boards together. Some vehicles with the VCM will display very erratic and unstable line pressure rise in the transmission, and in some instances, premature failure of the transmission.

CAUSE: Bad ground connection from one printed circuit board to the other.

CORRECTION: There is now available from OEM parts sources, a new service repair kit with an instruction sheet, to repair 1996 vehicles with this condition, and is available under OEM part number 12167310.

Step Number One:
Remove the wire and terminal from location 18 in the "Clear" connector, and install one end of the jumper wire that is included in the service kit into location 18 in the "Clear" connector, and reinstall the clear connector, as shown in Figure 1.

Step Number Two:
Install the wire and terminal that was removed from cavity location 18 in the clear connector, into empty cavity location 23 of the "Blue" connector, as shown in Figure 1.

Step Number Three:
Install the other end of the included jumper wire that was previously installed in cavity 18 of the clear connector, into empty cavity location 26 of the "Red" connector, as shown in Figure 1.

SERVICE INFORMATION:
Service Repair Kit......................................................12167310

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THM 4L60-E - LACK OF LUBRICATION

COMPLAINT: Vehicle is brought to your shop and has failed because of lack of lubrication. You check the cooler or possibly replace the cooler as a precaution. After replacing the necessary failed parts, the vehicle is returned with the same problem.

CAUSE: The cause may be, a defective pump cover (Stator) from the factory, that was not drilled completely through the "Lube From Cooler" passage, as shown in Figure 1. If this passage is not drilled through, there will be no lubrication to the rear of this unit as all lube must pass through the pump cover (See Figure 1). Every one that we have encountered, and we have seen several, had been drilled just deep enough that the cup plug that seals this passage after drilling was installed in the cover.

CORRECTION: Replace the pump cover as necessary with a new one and inspect every one that enters your shop to ensure no return failures. All of the pump covers we have seen at this point, were the 13 vane variety. Find more useful tools like Lexia 3 PP2000 and digimaster 2 to solve the car problems.