Ah yes, just like when I was new!
![Welcome :welcome:](https://board.marlincrawler.com/Smileys/marlin/welcome.gif)
Could be a number of things.
As easy as no fluid all the way to transmission going bad.
Check;
Fluid level
make sure no leaks
Adjustment of pedal linkages
Shifter seat
if that's not it then it could be the tranny syncro's or even carrier bearings. That's what happened to me last time, wouldn't go into any gear
![My Two Cents :twocents:](https://board.marlincrawler.com/Smileys/marlin/twocents.gif)