Today I installed a 722.3 in a 260e to replace the leaking 722,4

Went straight in.

(a) Had to change cooler lines - 722.4 are 17mm with smaller banjos at the transmission end. - 722.3 are 19mm bolts.
(b) Had to change the rear yoke.
(c) The pain if you are not electrically minded is that the NSS cable connector is different between the the transmissions. I ended up cutting the end off the 722.4 connector and splicing a 722.3 connector on. (there are only 4 wires involved and they are the same colours on each connector)

Speedo works fine.
722.4 Shift rod fitted straight in on 722.3

Sorry no images. I took a 2004 model point and shoot camera and put a SD card in that was too large for that old technology