I have had a similar problem with my TD4, usually when turning slightly, and usually at certain revs. I found the problem was that the vehicle had been grounded and one of the VCU support bearings was bent almost an inch out of allignment. Once I had replaced both and the UJ bearings it cleared...

And it wasn't a good service from me as I missed the fact that one of the driveshaft bearings has been knocked out of allignment by a good bit!

Mmmn, I don't think I have the same problem, after I gave the thing a good service yesterday I took it out for a run over a variety of roads/lanes. I can replicate the noise on in a straight line at exactly 1900-2000rpm when accelerating away. However it's worse if I'm turning right. I did have...

And I do too! - just bought my TD4 Commercial, worked on it all day servicing it, I can find no obvious faults. Right hand bend power on and it makes this judder/knock from somewhere on the front. Left hand bend is fine. At all other times runs like a good un. Phil. (also first post on forum)