These transmissions in this year were prone to problems. I’d guess an internal seal is leaking or a problem with the solenoid pack. Like Transman said, you really won’t know until a diagnostic is done. The electronic diagnostics on these are pretty good (as they need to be with this tranny) and will hopefully give you a working diagnosis. On the plus side, even if it costs to rebuild the tranny, a proper rebuild with the right parts will bring it up to today’s standards and you (hopefully) shouldn’t have any trouble with it for a long time. I went through this with my 94’ LHS.