occasionally when i try shifting from 1-2 close to redline on my 97 elantra. my second gear doesnt go in(which results in occasional gear grinding) it simply refuses to go in. similar effect as trying to put it in first gear at higher speeds which is impossible because the gear isnt syncronized or something.

 

Sounds like the syncro's wearing a bit. If you must change up at such high road speed, try keeping the engine revs up during the change. Chris.