I have a 1994 300 disco tdi.
When we get rain, it knocks underneath. Normally on braking or cornering/body roll. It doesn't do it in the dry, only when it rains for a day or two.
Anybody any ideas? I'm ruling out gearbox drive train as it's affected by damp conditions.
Incidentally, many of you helped me with a ticking noise last year. Thanks for that. It turned out that after replacing expensive parts such as the front pipe, some nerd had put number 4 injector clamp on upside down when it went in for a replacement cylinder head under warranty months before. Just in case you hear of this one again.
K