Blame the Torque Converter, Part 2

Last month, in Part I of Blame the Torque Converter, a 2001 Volkswagen Jetta and a 2002 Toyota Tundra were both thought to have faulty torque converters. Both vehicles had TCC related trouble codes (the Jetta had a 740 code and the Tundra had a 770 code). The TCC codes for both vehicles were found to have been caused by the installation of incompatible hard parts. The overdrive planetary gear set in the Jetta was replaced with an overdrive planet with an incorrect ratio. An overdrive planet was also the part that caused the TCC code in the Tundra, but for a different reason. In the Tundra the input shaft is an integral part of the overdrive planet and is available in two different lengths. The overdrive planet was the correct ratio, but the input shaft was too short to properly seal the TCC circuit in the torque converter. The following are two more examples of falsely accused torque converters.

2001 Chevrolet Impala 1811 and 741 Code

A 2001 Chevy Impala equipped with a 3.4L V6 engine and a 4T65-E transmission was towed to a transmission shop. The initial visual inspection revealed that the vehicle had the common differential failure, but since there were more than 100,000 miles on the odometer the customer was sold a complete rebuild. This turned out to be an excellent call on the shop’s part because the failure was more widespread than could be seen from the outside. When the unit was disassembled, the technician found that the splines on the 4th hub were almost totally stripped off and the plastic thrust washer that separates the drive sprocket from the drive sprocket support had disintegrated allowing metal to metal contact.

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

Article No.: TCTIP-10-08
Author: Ed Lee
Total Pages: 6

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