Our 2001 Excursion has an odd trans "leak".

It has only happened twice in the past 6 months, but the trans will pour out about a cup of fluid.

It looks like it's coming from the top of the trans and happens only after the vehicle has set up overnight or for a couple of days and is initially started up.

The trans does not otherwise leak or give up fluid during normal driving.

Any ideas?

Thanks in advance,

Peter