Success with the ATF change
Found a lot of old damage done to the teeth of the T55 recess in the plug. I had a Dealer do the ATF change for me last time. The Service Writer was telling the truth when he said the Tech had a heck of a time removing the plug.
Will definitely need to order a new plug for the next ATF change
I used a T55 bit, stubby wobble extension, 24-inch long 3/8 socket extension, a 3/8 to 1/2 adapter, and a 15-inch long 1/2 inch ratchet. Leaned on it hard to keep the bit in the recess and the plug finally turned. Leaning hard into the bit reduces the turning force your arm can develop, which is why I went to an extra long ratchet.