HI there the trans. service message actually has a bad name this means that the transmission control moudle has a code stored in it this could be from a slipage in the trans. or a bad sensor this would have to be checked out by the dealer or a trans. shop.
The trans dip stick is in the front of the transmission it is yellow in color and is down in front of the trans. and is only sticks up about 2 inch. from the trans. and is hard to get to
ASE Certified Technician
have worked on volvo's for 4 years and am a ase master mechanic. current shop foreman