Poo on my trans....

OK, Trans is not beeing nice. It is having an issue that happens when it is above 50 outside. The trans works almost like new when below 50. When above... I get noise when i let off the gas in overdrive... that simple. It is a grumbling/rubbing/ almost grinding noise. i know that it is in the overdrive because i can lock it out and have no noise. Also, it will occasionally jerk in overdrive also. The problem sounds electronic to me so i want to fix it before i cause anymore internal damage than already happend. I just dont know anything about automatic trans. It's an 87 cherokee 4x4 with the AW-4 auto.... someone help me.....