A Bumpy Cruze
Owners of a 2012-2014 Chevy Cruze equipped with a 1.4L engine and 6T40 automatic transmission and built before Aug. 1, 2013, may complain about a bump feeling or surge or an engine vibration while stopped at idle with the transmission in drive and their foot on the brake pedal.
This may be caused by the transmission neutral idle feature. When the service brakes are applied and the vehicle speed, throttle position and transmission temperature are within the calibration defined limits, the TCM (transmission control module) commands the transmission to neutral. The neutral idle feature will only function when transmission fluid temperature is 99 degrees Fahrenheit or greater. Verify that the transmission fluid is at 99 degrees F or greater before continuing with diagnosis.
When the condition occurs, move the transmission shift lever to the manual position. Moving the shift lever to manual will prevent the neutral idle feature from functioning.
If the concern is eliminated by moving the shift lever to the manual position, it is caused by the neutral idle feature and variation in the 1-2-3-4 clutch fiber plates. The 1-2-3-4 clutch fiber plates should be replaced with P/N 24268545. This is a kit that contains two clutch fiber plates. If the concern is not eliminated by moving the shift lever to the manual position, further diagnosis is required.
The clutch plates will only correct a continuous on/off bump, surge or vibration. These plates will not eliminate a single bump feeling that occurs when the service brake is released and the transmission engages the 1-2-3-4 clutch. The single bump feeling is normal.