4R100 Flow Issues

To help understand some of the flow issues that plague the 4R100 converter, it’s a good idea to look first at its ancestor, the E4OD.

The E4OD brought a new variety of TCC problems to transmission shops. The clutch crowding condition that was all too common in the E4OD had not commonly been seen by most shops until this time. Keep in mind that the only experience most shops had in diagnosing lockup problems was limited to the TCC shudder and engine stall problems of the early Chryslers. Since most of these problems turned out to be cooler flow-related, these early Chryslers didn’t help in the advancement of diagnostic knowledge.

Limited diagnostic abilities caused many of the initial clutch crowding conditions to be misdiagnosed. Most were diagnosed as engine performance problems – off-idle hesitations, engine stumble or lean fuel conditions. When the problem was finally identified correctly, it still took some time to identify the root cause. The technicians knew that the TCC clutch was dragging, but didn’t know why. It seemed natural to look for the root cause of the crowding condition on the apply side of the circuit. The hard lessons learned from troubleshooting the GM 125C engine stall problem were still fresh on most technicians’ minds. This kept them focused on trying to figure out how the TCC apply oil was getting into the converter when it wasn’t supposed to. Only when the TCC apply passage between the solenoid pack and the pump was tapped did their focus change.

To read the rest of this Technical Article on the Sonnax Website click here.

Article No.: TCTIP-05-06
Author: Ed Lee
Total Pages: 3

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