1996 Monte Carlo Transmission Problem

It’s my wife’s car & she hardly ever drives it. Only has 88,000 miles on it. So, occasionally I use it to run an errand. Reverse did not work the last time I tried to back out of the garage. I added some transmission fluid, let it idle for awhile and got it to move some - but with the wheels still binding a lot. What else can I try at home, before giving up and having it towed to a mechanic?