Transmission trouble
 

Transmission in 07 S60 2.5T AWD slipping out of gear when stopping. Indicator on dashboard shows a dash when this happens instead of a D and transmission service light comes (stays) on. Wife shuts car off and restarts when this happens and it goes back into gear until she stops again. I dont know if just switching the gear shifter to park and back will work because I haven't tried myself nor has she. Can anyone share some knowledge regarding this issue?

You could have any number of issues causing that including a failing gear selector switch. The fact that the "D" disappears suggests that the problem is electronic in nature.

PM me and we can get together on some suggestions.