Why do automatic transmissions lose overdrive, in late 1990's GM cars?

Probably 90% of the time if you have trouble with an automatic its because you got it too hot. Trying to pull too much weight, trying to climb too steep of a hill, or being in too high of a gear will make the transmission get too hot. Its important to keep it out of overdrive when your pulling any amount of weight. Some are just more prone to problems than other because of a bad design. I have heard that some will lose the overdrive clutch packs and in some the drive bands will snap.