This transmission was built in France, then shipped to Japan, to install in out trusty steeds...
France has always liked to be on the cutting edge of being, "different" or is the more approiate word, "strange".....
I would order replacement plugs from Isuzu then r&r..but beware this may be a "re-threaded" replacement and the stock no longer fit'sPerhaps the previous owner did this masterpiece