Go to the parts desk at your local dealership, they will be able to bring up a breakdown/parts list of the gearbox/shifter assembly. Then u will just need to pinpoint the actual rubber bush that needs replacing. (It should be in the actual shifter/tower/lever assembly- so places like autobarn and supercheap probably wont have it on file in their listings).
I also have no idea what it is called, but i know exactly what u r referring to.
but, once the knuckle on the shift lever bottoms out against the shift fork/rail internally, it should still move - with a feeling of resistance (depending on how hard u push downwards of course)
Unless ofcourse the vt/vx 5Ls came with the 6spd that had the detent for reverse which requires the stick to be pushed downwards to select reverse( in which case putting pressure on the stick will limit u to selecting reverse), OR, the finger lever on the stick which has to be pulled upwards to select reverse
...OR im thinking of the complete wrong gearbox and the 5L manual had none of the above features, in which case u just need a new rubber in the shifter
