Sadly it's worse than just the turbo seals.
When it went it produced more power than the torque converter could handle. We were doing 70 up a hill in the fast lane, and it started to accelerate and over-rev. My first thought was that the autobox was low on ATF, as I couldn't understand why the revs went so high, but when I took my foot off my throttle and it carried on and I realised it was a runaway.
We made our way to the hard shoulder while braking (the Delica has some hefty disc brakes all round - very glad of those), during which it started to calm down on its own (plan was to jam the autobox in reverse, and if that didn't work jump out and cut the turbo hoses off with a knife I carry on the toolbox). So it didn't carry on running away, which is lucky. But the overrun has blown some seals/gaskets somewhere because oil was running out from the IP side of the engine (opposite side from the turbo).
It might just be the IP to engine o-seal that let the oil out (it never was seated well) but given the welding and other things going wrong with it, it's getting a bit beyond the point where it's worth the effort.
Question is whether to get another one, since I now have spares aplenty
