R34 GTR Getrag 6 speed gearbox issue

[Brandon_1994]

R34 GTR Getrag 6 speed gearbox issue

Hi there,

having issues with my R34 GTR gearbox just seeing if anyone has come across this issue before.

Its the standard 6 speed getrag box, with upgraded clutch (Twin plate os giken)

The car has tuned 650hp, but issue was here before that

5th gear synchro was busted and 5th gear would work very randomly but most of the time would not go in.

5th gear synchro has been replaced since and would only work 75% of the time but still does not like to go in

it will go in 100% of the time if you rev up before shift

will go in on idle 

The oil in the gearbox is new Castrol Transmission fluid z, has had the issue prior to it with the same oil

All other gears are fine.

Just seeing if anyone else knows what the issue could be, and if anyone else has had the same issue on their 6 speed box..

Thanks in advance.