Transmission slipping when hot?

I have had a Turbo 350 slip in the opposite situation.... slipped when cold but was fine when warm. No burned smell in the fluid or discoloration. Tore it down and the problem was obvious: the friction material was mostly worn off on one pack of clutches and the metal backing was showing on all of them to varying degrees in that pack. You could just have a worn out trans.....since it is original; that would not be too surprising.