I had this exact problem with my 94 about 2 years ago. I called the dealer and they said that sometimes the fluid will leak out of the resevoir around the metal lines that go in. They recommended that I refill the resevoir and monitor the level for a few months. If the level is going down, they would need to repair it. I did this and the level has only gone down ever so slightly in 2 years.

I would start by checking the fluid and monitoring it. If the fluid level is not low now, then there is another problem somewhere else.

Mish