jazzfan4u

I have a 97 Civic LX that will not shift into 3rd or 4th gears. When this problem originally came about, It would not shift into any gear. After sitting for a couple days and after towing, it did shift rev, 1, 2 and 3 but still no 4th or 5th. I'm wondering if this could be a bad transmission. Any input is welcomed as I'm a newbie at the diagnosing of such problems, however, I have the knowledge, skills and equipment to do the work myself. Thanks!