Rattling in gearbox clutch disengaged/neutral

[Paymh]

Rattling in gearbox clutch disengaged/neutral

Hey guys so been trying to track this issue for ages. When going over bumps or turning a corner/reversing with the gearing disengaged/clutch partially engaged the gearbox rattles heaps. Can physically feel all the gears rattling inside the gearbox and its real loud.

The cars a r33 gtst with a tight shimmed diff i originally thought it was because of the diff being locked but since it happens going over bumps im not so sure...although its much much worse when reversing while turned.

This issue leads me to the next problem which is a grinding between gears which i first thought to be the syncros but the issue is so much worse if you're mid drift and try to shift it grinds so much worse which i think stems from the above rattling as i pushed the clutch in to shift and the gears bounce all around the joint...

Tranny mount when i bought the car was as loose and worn as an old hooker its since been made solid with polyurethane, all rear bushes replaced cept stock diff bushes, subframe collars, no difference made with those changes. Not sure what it could be. Don't think its engine mounts because its only with clutch disengaged so shouldnt matter..Thoughts lads? Thanks!

[GTSBoy]

Input shaft bearing stuffed.  Or something equally bad.