Torque converter forensics

Three preventable bearing failures

When a torque converter fails, the results are quite often catastrophic. It may be difficult to determine which component failed first and even more difficult to determine the root cause of the failure. Each failure should be viewed as an opportunity to learn, and a failure that is caught before the catastrophic stage should be viewed as a golden opportunity.

Here are three converter failures that were caught in the early stages. The customer complaint on all three converters was a noise. The noise was qualified by determining when it occurred. The noise wasn’t audible in neutral or park, but could be heard in all drive ranges, forward and reverse. The noise also increased with the load that was placed on the converter.

The first converter was a 4R100. It was replaced a few weeks prior to the noise issue, while the customer was on a trip, and the distance to the original shop prevented the customer from returning the vehicle. The local technician checking out the noise felt that it was inside the converter because it was present only when the transmission was in gear. He also eliminated the transmission as the source of the noise because the noise was audible when the vehicle wasn’t moving. When the converter was removed, the overall height and endplay were checked before the converter was cut apart. Both checked within OEM specifications.

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

Article No.: TCTIP-10-07
Author: Ed Lee
Total Pages: 2

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