gearbox rattle

[Opntop@aol.com]

Hello all ,there is a rattling noise coming from my gearbox that sounds like 
a loose ball bearing that stops after well warmed up. If Iput very slight 
pressure on the clutch pedal it stops . I suspect the throw out bearing . 
Also when I put reverse in I grind the gears even at normal idling . Are the 
2 problems related ? Is it a must fix it now thing ?
Thanks.
Sal
TR250