4 Speed 2nd Gear Question ?

Be sure to check that side cover and the detent mechanism. I've seen this before but every time it was a bent or twisted shift fork. The first-second syncro slider is a big heavy thing with half of reverse gear riding on it and it takes more force to power shift that 3-4. If a brass syncro blocker was busted, it would spread when applied and the cone clutching action would not occur, thereby preventing the matching of the gear speeds. It would not shift and if it did, it would really fuss at you! If it shifts, it's not the blocker ring. I broke a 1-2 shift fork at the strip in my Hemi Roadrunner. The originals were brass. Ronnie Sox and Jake King gave me the part numbers for new steel ones. I don't remember the numbers but you can get them from Jamie at Passon Performance. Google Passon Performance. By the way, are you using a Hurst Competition shifter with the "syncro lock" feature? These are two bolts with lock nuts fitted in the front and rear of the shifter body. They were designed to prevent over-running of the syncro slider. If the bolt is in too far, it will prevent full engagement in the tranny. Good luck, I hope this helps you.
Pat