Converter charge oil performs a number of important functions. It fills the converter in a timely manner. It keeps the lockup clutch off the cover in the release mode. It also eventually becomes the lube oil for the transmission.
When charge oil is not flowing at the correct rate, the converter will operate less efficiently, the lube oil to the transmission will not be adequate, and the lockup clutch will drag on the cover in the TCC release mode. The TCC apply can feel more pronounced and could shudder because of a greater differential in turbine RPM. Delayed engagements, higher stall RPM, poor acceleration and a drop in fuel mileage may also be symptoms. Low charge oil will also affect temperature levels and the head pressure within the converter. How pronounced these symptoms are depends on the lack of converter pressure. The lower the charge oil, the worse the symptoms will be.
How many times have you heard an R&R man complaining about how slowly the oil was going down the fill tube? Quite often there was a good reason why this was happening, such as a restricted vent, the wrong filter or elevated line pressure. Then there were the times when no good reason could be found. There may be a logical explanation for some of these mysteries.
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Article No.: TCTIP-01-07
Author: Ed Lee
Total Pages: 2
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