Is it the T word? Update

Thanks to all for the very helpful ideas about my Saab’s reluctance to work in reverse. (Loved the definition of AAMCO: All Automatic Transmissions Must Come Out!) I’ve had the fluids checked by our mechanic. All’s well on that front, so he’s recommended a good local transmission shop to see if they can diagnose the problem. I’ll mention that the problem is worse when the nose of the car is facing downhill. On flat surfaces, reverse works better when the engine is warm, and in general the reverse function is unhappy in really cold weather. Is there any other info I should be gathering to help the mechanics? Thanks in advance!

If you give them the info you gave in this post, that should suffice.