WARNING: This page is about a different car, the 2002 Volvo C70, 2001 Volvo C70, 2000 Volvo C70, 1999 Volvo C70, and 1998 Volvo C70. However, it is still accessible from the selected car via links, so may be relevant.
Fig 1: Oil Level Plug
Courtesy of VOLVO CARS OF NORTH AMERICA.
Remove the level plug and fill with oil. Use only Volvo transmission oil P/N 116 1745 (1 liter). Volume in the transmission 2.1 liters.
Install the level plug with a new gasket. Tighten to 35 Nm
.