Was driving Superblue the other day and was curious at which speeds is the trans supposed to shift gears … Seems she goes from 1-2 around 20 mph, 2-3 around 52 or so mph, and I have yet to have her up to 3-4 speed in a long time (I do NOT like highway driving 
) so no idea on that one. I couldn’t find any of these specs in the factory repair manual set.
From memory its like most other autos, the further your foot is into the carpet the later the trans changes 
I do recall the trans ‘locks up’ around the 50mph mark, denote by a small lurch. This is from my time with myXJ40 which uses the same trans as your I believe.
Yes, and was gonna ask about that “small lurch” … Which almost feels like the tranny is slightly slipping and then suddenly engages … i.e. is that “normal” ? Sounds like it is … 
Yes it is normal…