From your video I can hear a "whirring" sound. Is that the sound you're talking about? My very first 98+ tranny did that exact same thing. Nissan dealership immediately ordered a replacement saying the noise wasn't normal. It took 4 transmissions before they finally got me a good one (one that wasn't noisy and that wouldn't grind/crunch 1>2 gear). I've also been using the Nissan OEM 75W85 manual transmission fluid. Out of all the fluids I've tried,this one is hands down the very best.