clunking noise..

I went to reverse of the drive this morning and my freebie made a sort of clunking noise from the front and somthing seem to move at the front underneath.

Drives fine besides this, any ideas what it could be or what to check?

52 td4 auto.

thanks

You have run over the postman.

Well, it could a several things. Ultimately something moved that normally shouldn't. Get it on the lift, undertray off and have a look. Things that I would check for starters.

Lower engine strap.
Front driveshafts and CV's
Central shaft knuckle joint
VCU bearings
Rear diff mounts (it might sounds from the front but this is a known faults)
Anything else that is floating about that shouldn't be.

Keep a very close eye on that IRD, it might have been the pinion gears...