Finally got around to this. No shifting issues at all but 18 year old fluid with 120k miles on it probably needs changing. I was expecting to do the Dell method:
https://www.jaguarforums.com/forum/x...0/#post1700527

Based on that post I was expecting to drain about 3.5 quarts (14 cups), fill, run the car, drain about 3.5 qts, etc. I was quite surprised to find my initial drain was nearly 6.5 quarts. The workshop manual says the total dry capacity is 8.2 qts so with 1 drain and refill I am at about 80% fresh trans fluid already. Now I begin to wonder about how much new fluid is "good enough".

I used the SwingWing (and other users) recommendation of a turkey baster jammed into place with a rag as a fill tube extension. Funnel on top of turkey baster. I managed to pull the rubber bung from the fill tube easily by hand. Having skinny arms finally pays off. Putting it back in was a little trickier but I managed to hold it in place with my left hand then jam it down into the hole with a dowel in my right hand.

Old fluid was black and watery but smelled like trans fluid. I did not get the "swamp water" smell others have mentioned.

 

I think bugger all of that ineffective and wasteful repeated drain and fill method - this is what I do:
https://www.jaguarforums.com/forum/x...change-266693/