Metallic rattling from gear shift?

[Tman]

At high speed and revs I'm getting a metallic rattling sound coming from the gear shift? It doesn't sound serious but is a bit irritating after a while - any ideas what it could be?

[NCE 61]

Collar under the gear knob could be loose.

[whitey]

you sure it's the gear knob? It might be the button on the handbrake which vibrates if it starts to unscrew itself. Turn clockwise to repair

[andyoleary]

ditto on collar under gear knob - puzzled me first time it happened....