Good to hear there are two other 4x4s with the grinding/vibrating/chatter noise around the 50mph mark. I thought it was around where the transfer box is as is where the noise comes from if I had to guess, but I have not asked my wife to hang out of the window or let her hang underneath while going at 50mph to see if she can work it out. I do have access to a commercial pit and some experienced non-Mercedes mechanics who are used to working on 814s but not 4x4s. Maybe we can find the location of the problem somehow.Maybe even to rebuild the box and look at the bearings over the winter
If I locate the issue I'll post up what it was and costs etc so you can see if its worth doing yourselves.
After all, we all know its worth keeping things in good condition while we all drive on to the 1st million miles. :costumed-smiley-007
Cheers all.
Steve