I had the grind in 4th and 5th, switched to redline MT-90 and the grinds were totally gone. I've been running the MT-90 for many years now and the grind has never come back and I've never had any other transmission problems.
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90 300zx TT 13.285@106.08 (old stock turbo set up) 94 Camaro Z28 13.751@101.83 03 WRX 13.973@94.88 02 Mazda MPV; four kids and a wife don't fit in the Z. 90 240sx (sold) 16.9@87