Here are some links for you
PeachPartsWiki: MERCEDES-BENZ TRANSMISSION
http://www.peachparts.com/shopforum/diesel-discussion/237763-my-superior-shift-kit-thread-w124-300dt.html
The ATSG manual says
1) Check modulating pressure adjust if required
2) Check whether temperature is installed
3) Exchange shift valve housing
4) Recondition K1 clutch"
Option 1) is vacuum adjust
Option 2) must have a word missing - I don't know what that's all about! Can anyone help?
Option 3) that's all the superior shift kit type stuff moving onto more expensive options...
Option 4) that's a bit more work - but probably not too expensive in terms of replacement parts (clutch discs for the 722.1 come in at about 7 euros a piece)
'Hope this helps