When was the last time the pan was off and cleaned? Those could be original shavings.
Could also be evidence the OD switch was misdiagnosed. I am very skeptical when on the road.
If it is a nationwide warranty I might go for the transmission. Otherwise I would drive a bit slower and cross my fingers to get home.
Last Summer I drove home 1500+ miles manually shifting my automatic because it had issues. Had the valve body rebuilt upon return.
I would be looking for a remanufactured transmission exchange with a national three year warranty if replacing on the road. And the shop could be really great and it lasts ten+ years. Hard to know.
Good luck.