GU6 Manual getting hot

[Scorpiovee]

Hi all, any input/thoughts or fixes would be much appreciated.
So here it is. A close friend of mine has a GU6 DX same as mine. Has had a new clutch installed after 85000km, (ex mine truck) and now the gearbox is getting rather warm. I've suggested to him that the spigot bearing may not be seated right, putting either pressure on the internals or wobbling while driving. The heat is coming through the floor (nice in winter, not so nice in summer) and up through the gearstick. Mechanic that did the job doesn't know why, but is adamant that it has nothing to do with the work he has done. It still drives fine, but it's getting so hot that you can't rest your leg on the tunnel. Strange thing is, sometimes it will run cool, but it runs hot more often than not. Can also smell gear oil, but no leaks have been found.
It does it on long runs, short runs, heavy, light and even on cold days.
Thought I'd ask you guys here before I drop the box out for him.
Cheers V