Strange noise W123

[kdlemon]

It sounds just like a metal engine fan hitting a metal radiator shroud.

The car is a 280E. It makes the noise only when the car first gets rolling from a standing start and when braking ubruptly during reversing. The motor mounts and the transmission mount have been replaced but the noise is unchanged.

It seems to come from under the car. The exhaust does not seem to be hitting anything and it is a rotational noise rather than a rubbing or knocking.

Front pump? It has the old style transmission.

Thanks guys!