Farmall Cub

I have a LoBoy 154 that pops out of reverse gear. If I hold the shifter down, it doesn't do it. None of the other gears have this problem.
I took the transmission cover off and the shifter forks are not bent or worn excessively, but I do see some wear on the reverse gear.
What's the most likely cause of the problem?
Thanks,
Charlie

Check the first and reverse fork for looseness or fronmt to rear wiggle. Only a loose fork can pop it out of reverse or first as it gets worse. They tighten up the fork and tac weld the gaps. Most do it while the tranny is together by packing the tranny with old leathers. It can be done with success very carefully.

I found the problem. The shifter forks were not loose nor were they worn excessively as stated in my first post. The reverse gear was quite worn and the first/reverse slider gear had some wear also, so I replaced those two gears. It now stays in gear just as it should. Not a particularly hard job to fix it. The biggest part was to remove the 3-pt hitch so I could get to the differential cover and remove it so I could get access to push out the shifter rods.
I learned on an earlier job that it's best not to push the shifter rods all the way out of the casing and avoid having the ball and spring fly off into outer space!
Charlie