Jeremyonealmyrick12101980

I have a 1994 GMC k1500 4x4 pickup w/4l60e transmission in it. Five years ago it started shifting hard from 1st to 2nd. Starting a few months ago the overdrive would all of a sudden stop working going down the road but would start working again a few miles down the road. All of a sudden 2nd and 4th stopped working about two weeks ago so I only have 1st, 3rd, and reverse. No 2nd or 4th though. A couple days ago coming home from uptown the 1st gear stopped working and I only had 3rd gear coming home but the reverse still worked. I hopped on it today and 1st gear worked just fine again. But still no 2nd or 4th gear. Reverse still works just fine and has never stopped working. And when 2nd and 4th stopped working it showed no signs of slipping at all. Can anybody help me out and give me some idea as to what the problem might be. I'd appreciate it.