The following is the information that has been provided by our product support division in relation to the XC60 transmission shifting feedback and inquiry you reported.
The 6 speed in the XC60 has been around since 2006, and has demonstrated exceptional reliability. The original software in the transmission was programmed to keep the transmission in gear from coast down to assist with a mild engine brake feature. Once the car reached a speed of approximately 30 km/h, the transmission disengaged and prepared its self for acceleration again. The consequence of this was that in certain light braking application, the action of the transmission was felt as a mild jerk during coast down. This was magnified in cars with worn engine mounts.
To address this, the software was modified in 2012 to hold the gear and shift to 2nd unless the car came to a complete stop. When you accelerate from an “almost” stopped speed, the car starts up in 2nd gear to provide a smoother coast down experience.
Unless of course there is a demand from the driver for more power. If there is a demand for additional power, the shifts to 1st gear, which can be felt as a bump at low speed take-off. This is magnified on inclines as:
The throttle application is greater
Throttle command is temporarily reduced at the throttle plate to facilitate a smooth shift
This feeling is often interpreted as the transmission slipping or engaging poorly, but is instead how the transmission is designed to operate without consequence to long term durability. The ‘slip’ feeling is a combination of throttle reduction and transmission delay to avoid a harsh jolt to the driveline. The failure rate on this series of transmission is extremely low. This can be mitigated with a smooth dip into the throttle during rolling accelerations which don’t make the car think that sudden power is required.
Software is available to return to the original design, but there are trade-offs there too. Polestar software does not change the transmission shift logic. The software in the 3.2 is different to match the different power and torque curves in the 3.2 vs the T6. This gear hold logic is undesirable in the 3,2, as the engine needs to rev up to make power, vs. a T6 which can have power at low rpm’s due to electronic turbo boost control. Different drivelines cannot really be compared.
This is not of course to ignore that transmission fluid on all cars degrade over time losing its properties and hard shifting is often the first consequence. Fluid colour/ inspection should also be inspected to determine if transmission performance can be improved.
I hope this has provided more insight on the transmission shifting properties of the XC60 and that it is consistent with your observations. If you have any further questions regarding this, please contact Ivan at Newmarket Volvo as this is the extent of the technical information that can be provided through Customer Relations. Our retailers are the point of contact for inquiries of this nature as they have factory trained technicians as well as direct access to Volvo Technical Support.
That being said, please be assured that we have documented your feedback on this topic and we would ask that in the event that further transmission concerns occur, please notify Newmarket Volvo and we will review the case for assistance, but at this time it has been determined that the transmission in your 2011 XC60 is functioning as intended by Volvo.