Water contamination in torque converters

Opening up a torque converter and finding what looks like a strawberry milkshake inside is fairly common in the rebuilding industry. The strawberry milkshake appearance is the result of ATF being contaminated by water. A small amount of water mixed with transmission fluid will change the appearance of the fluid dramatically. Since many shops have limited areas available for storing cores, some cores are open to the elements. Transporting cores in open vehicles also increases the opportunities for water contamination.

A small amount of water in a non-lockup converter is usually not a problem, provided it is removed in a reasonable amount of time. However, if the water remains in the converter long enough to show signs of rust on the ferrous metals or oxidation on the non-ferrous metals, you will probably have either bearing or stator clutch issues. There are additional concerns with water contamination in a lockup torque converter. With the exception of high carbon or woven carbon friction materials, all lockup clutch linings are paper-based. When a paper-based TCC clutch is exposed to water, it’s only a matter of time before a failure occurs. The friction material will either delaminate or the material will separate from the piston at the bond line because of
rust.

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Article No.: TCTIP-08-06
Author: Ed Lee
Total Pages: 2

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