I have a 1992 GMC K1500 with the 700r4/4L60 and this morning I turned off of my dirt road and heard a big pop and then revs sky rocketed. Turns out now when I shift in to O/D it acts just like another neutral. If I shift into drive I have at least 1st and 2nd, limped it back home so it didn't get into 3rd, and reverse works as well. And ideas what happened or any hopefully easy fixes? Or is it time to bite the bullet and rebuild it? Thanks