I have a 2011 S80 with < 50K miles. As I am slowing down, at the point before a complete stop, it feels as if the engine shifts down. It is a hard shift. Also, if I let up off the break as I reach stop (but not stopped) and push the accelerator (not hard), it feels like a down shift.

When the car was in warranty, they did download code and it fixed it for a short time. Not sure this was the solution to the issue.

Any ideas?

 

Looks like this was your only post from back in 2017 so I'm guessing the issue was not resolved. I too have a 2011 S80 (non turbo) and get a hard downshift at around 26 mph when coasting. Seems to go away when car is driven hard. Took it into dealer (I bought it used a few months ago and all maintenance was through dealer) and they said the transmission needs a software update but the current computer needs to be updated first. That seemed a bit weird to me.
Anyway, if anybody gets this and can provide info, I'd appreciate it. You might see replies from me elsewhere.

BTW this is my first post on this site!