The owners manual says it does but to be honest i haven't looked yet, one ray of sunshine in all this is i think i've got to the bottom of the knocking noise when on the move, one of my work mates suggested that i pop the Disco up on axle stands and he'd have a look for me, all the UJs seemed ok as did the diffs but a casual kick of the nearside front wheel revealed something alarming....the wheel nuts were virtually off and the wheel was as loose as fook, done them up tight and took her for a drive and hey presto no noise!, quietly optimistic that this was the problem all along but i'm going to give it a week or so of driving to put my mind at ease.
p.s. made sure i checked the other wheels as well! lol