Under the loads that a transmission sees there is no way that old transmission fluid is going to be sticky enough to hold little pieces of metal in place as if there were no worn spots. If the tranny were worn it would show signs of that especially with old fluid.
I worked at a tranny shop and never once opened a tranny and found it held together by old tranny fluid and metal flakes. Yes, sometimes there were buildups of junk but never in the high wear areas.
Everything should be fine. Just change the fluid at the recommended times.
Paul
