The higher pitch is me blipping the throttle. When coasting it's quite and on acceleration where the engine is actually pushing i.e. going down hill faster than gravity, it has this whine. The last transmission flush had an inch of shavings on the magnetic drian plug. I have a 4 speed 260z and a unknown welded diff. Plans to swap out to spare open diff. and swap in a 5 speed 240sx transmission. Any info on that swap would be helpful to have!!! PS 75mph is actually 60mph