Spoon Sports 1/18/2012My uncles car does the same thing. He hasn't been able to find a permanent solution yet, however; He found out that if you go buy a code reader, hook it up, and erase any codes while you have the shifter in reverse, it'll normally go into gear. It's pretty simple really. It doesn't always work though. He has to do it a few times for it to work, and it hasn't failed him yet. (knock on wood).
Otherwise, only a tranny tech can provide a permanent fix