Sounds like the gearbox is dead. A slight chance would be be your clutch isn't disengaging properly.
Changing the diff would have zero impact on being able to select any gear. I'm surprised you thought it would. ...
What makes you so sure nothing nothing is leaking above it from that photo?
The bush hasn't let it's juice out because it has no liquid filling to release.
How long have you had the car? Could someone have lubed up the shonky old bush?
Could there be leak above from the rad or power steering?
I would much prefer to cut and re weld the manifold than to f**k around with a spacer like that.
Better yet. I would be pushing for Kyle to cut and fix the manifold.
No one that I know of is using one.
That's not cool your manifold doesn't put the turbo in the right place
Iruvyouskyrine has the same issue.
Makes you wonder ......
As per PM try this thread
http://www.skylinesaustralia.com/forums/topic/442062-33-gtst-wont-start-with-power-fc-will-with-standard-ecu/?fromsearch=1
Posted for future reference.
Think what you want.
I can read all but one word.
You can assume what it is.
I would bet it is insert.
Anyway, whatever.
I don't care if you believe me or not I also don't care if you fix the problem.