Trans fluid where it shouldn't be found

how does trans fluid get into throttle housing, connecting tube, air filter, and oil pan?

I can’t think of a plausible way this could happen.

Make, model, year? Don’t some transmissions have vacuum modulators that can bleed fluid into the intake if the diaphragm breaks? Oil pan?

There is a duplicate thread from the OP indicating it’s a '92 Olds. I didn’t think they were still using vacuum modulators that late.

this has a few mechanics stumped, possible manifold gasket, head gasket, none are sure. vacuum gasket{diaphram} i will be checking since its nearest the intake. oil level goes up, excess is drained when needed and new oil added. does not keep car from running good, except for smoke at start up and sometimes while driving

This does sound like a trans vacuum modulator leak. If it is, don’t forget to change your oil & filter and clean out your air inlet system after fixing the vacuum modulator.

replaced faulty trans modulator, which has a vacuum line, trans fluid was being sucked into air intake manifold and from there to air filter, and thru engine to oil pan, problem is solved

Just curious: What did your “stumped” mechanics say when you told them the source of your concern? They really should have not missed this one.