knock knock whos there ?

I have a knockin sound coming from my 2001 td5,if your sitting in the drivers seat it seems to be coming from the area to the side of my left leg.It usually happens when i'm driving up hill and if i hold onto the low/hi range stick i can feel the tapping of whatever this is coming through the stick.Can anyone help on this problem or has anyone had the same experience as me ,any help would be great.Ta

could b stuffed uj's........stuffed gbox mounting. get unner it with a crow bar and check everything under there for movement

Thanks for that will do when i get a chance.