Why is it that transmission problems are avoided by replacing them with reconditioned used transmissions, especially with slipping issues. Is it really that time & cost consuming to rebuild rather than replace with used ones? When does a manufacturer of transmissions consider a stop of production of a particular model, thus forcing consumers to resort to salvage yard replacements to maintain their vehicles in the long run?

When first starting up (cold engine) there seems to be a transmission slipping problem. Goes away when warming up.