Finally looked at your pictures. As Kit suggested, you might want to carefully play with the clamp/hose etc. where it connects to the reservoir. Maybe only a tightening is in order at age 23? My 90 240 weeped there as well. I have seen a few different Volvo models weep there over the years. Also check the condition of the hose and look for cracks in the reservoir while there.

With this ATF fluid controversy, if the problem is indeed that the rack seals are leaking on your 97 960 it might be easiest to simply convert to synthetic. Any quality synthetic should be backward compatible with Type F and G fluids. But for your peace of mind you should confirm this.

Must be all to obvious that I'm sold on the performance of synthetic fluids...:) Used them for years in my car's engines, transmissions and PS systems.
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Will I buy another Volvo??? We'll see....