I found this pdf with info on shift points , fault codes and diagnostic info wich i think can be helpfull when dealing with troubled transmissions.

A lot of interesting stuff.
It is a Mercedes document , so read around the merc type numbers etc. and be aware that some data may not be usefull with our cars.

 

this is awesome...thanks for posting it...i love how complex the XJR transmission are...they are like mechnical computers...

 

One of the diagnostics observations is the 4-5 upshift @ 155MPH.

Wonder how long techs keep their driving licences