1996 was the first year for the light pressure turbo. The high pressure turbo was in the Turbo, T5, and R models.

Most dealers only use regular oil, I suggest using synthetic exclusively. It is cleaner, keeps its viscosity longer, and lets you stretch oil changes to 5K or 7.5K for highway miles.

The need to use the shift overide can come from several places. There is a micro switch to the right of the shifter under the console that could need replacement. There is also a cable behind the keyed portion of the ignition switch that could use some oil, a pain to get the plastic off the steering column - 4 torx screws, 2 different sizes, and a 5 inch reach for 2 of them.

A dealer inspection will reveal all for about $100. You should do this, hust to know what future problems are lurking about.

If the oil leak is on the passenger side, it is probably one of the 2 oil cooler lines. A little hard to see what you are doing, but satisfying to DIY.

Klaus
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Why are Volvos so endearing? Its just a car.