[CrazyBRONCOguy]

Agree on checking what is there.

Could also be convertor drain back. There is a check valve in c6 that is suppose to keep this from happening, sometimes they can do it from the cooler line as well (they used to make a kit to put check valve in the cooler line). While I do think likely something else is going on making the dipstick tube come out. The fluid drain back issue may explain why it happens days later, as it gets enough fluid to actually come out of the dipstick hole drained back into the trans itself.