Just put Nippon Oil Co's "Eneos" full synthetic fluid in my gearbox. It was a toss up with MT90, but my local rice shop guys suggested I try it. They use it and have been getting good reviews from their customers. Pulled out of the driveway, made the first 1-2 shift and immediately noticed a difference. Drove straight to their shop and bought a few more quarts for the Dif. YMMV
Japanese fluids developed for Japanese cars can't be too awfully wrong..
Nippon Oil