Final drive oil replacement....

[Diesel]

http://www.st-owners.com/forums/showthread.php?76368-ST1300-Final-Drive-Oil-Change

[Bruce]

Good idea to have a go at this at least once. I did mine at 8 000 k and the magnetic plug had picked up that many shavings that it was 5 mm out of the plug. I presume that this was from manufacture. Checked again at 15 000 no shavings.

[saaz]

I would also suggest using a full synthetic oil.  It only uses a small amount and you don't have to do it very often. In a car I had the diff was really noisy and changing the diff oil did nothing to improve it. I used synthetic and the noises just went away.  If it can do this for a problem diff, then it should help the life of the diff while in good condition.