Some 2016-2020 CT6 and 2017-2019 ATS and CTS models may experience a fretting condition. This condition may cause a whining, whistle, squeaking or groaning sound during low-speed driving maneuvers (up to 40 mph or 64 km/h). Customers might describe the sounds to be coming from the engine or front wheel area.
The fretting occurs between the front intermediate shaft (IDS shaft) (Fig. 7) and the front intermediate shaft bearing/housing (IDS bearing) (Fig. 8) as a result of the slip fit interface between the bearing and the IDS shaft, combined with a bearing that has approximately 0.5 Nm of torque to rotate (TTR). This may also cause red dust/debris to appear within the IDS bearing/housing.
Fig. 7
Fig. 8
To identify this condition, perform a road test to verify and diagnose the customer concern. Try and replicate the customer’s driving maneuvers when the sound occurs. In most cases, the sound is heard while coasting without the brakes being applied.
Use the J-39570 Chassis Ears to determine if the sound is at the front intermediate shaft housing. If the sound is confirmed and isolated at the front intermediate shaft bearing/housing, replace both the IDS shaft and IDS shaft bearing/housing. Refer to the Front Wheel Drive Intermediate Shaft Replacement and Front Wheel Drive Intermediate Shaft Housing Replacement procedures in the appropriate Service Information.
Refer to #PIP5785 for more details and parts information.
– Thanks to Steve Schipansky and Scott Lewiston
Updated March 15, 2021
