If you have a rod shifter you might want to check the bolt that holds the support rod into the tranny housing.
The reason I say this is because my car was hard to shift for a while until one day, I totally lost 2nd, 4th, and reverse... there was just nothing there. Turned out this bolt fell out allowing the support rod to move back instead of the shift rod moving forward.
Now I don't think this will be your problem, if it's only having trouble in 2nd as mine was hard to shift in every gear, but it's easy to check.
Also, in case by some freak of nature this IS your problem, you'll probably find that the bolt in there is a grade 10.9 - 12mm by 1.75 pitch bolt and is about an inch shorter than it really should be so only about 3 threads hold it into the housing. From what I understand after researching my problem, a lot of people had used just threaded rod in there to remedy the problem. That's all fine and dandy, but I found that flexes a LOT compared to the original bolt, so I ordered a grade 10.9 bolt to fit. The bolt I have is 150mm long compared to about 120mm from factory. I have about 8 extras, so if you want one, let me know. After I put mine in, it shifted real nice again, not as vague of a feel as with the threaded rod in there.
This is just my experience with hard shifting, and like I said, I doubt yours is the same problem... but good luck.