Cleaning the input shaft
WARNING: This page is about a different car, the 2004 Volvo S40, 2003 Volvo S40, 2002 Volvo S40, 2001 Volvo S40, and 2000 Volvo S40. However, it is still accessible from the selected car via links, so may be relevant.
Spray universal oil (part no. 1161657) on the splines.
Brush with a brass wire brush.
Wipe the splines clean.
Repeat the cleaning process one more time.
Wipe the splines clean thoroughly.
check that there is no damage or dirt left on the input shaft.