Honda Odyssey 2002

I just took my Honda Odyssey 2002 in for the transmission recall. They
apparently did not find anything wrong with it and added an "oil jet
kit" that is supposed to keep the tranny from overheating. There is
something wierd that happens when driving around 35-30 mph. It is as
though someone is stepping on the clutch (although it is an automatic);
The engine revs, but the gears are not engaged. I have had this happen
to me before on a Subaru when the transmission fluid is low. However,
the tranny fluid on the Honda is not loww (a little bit high if
anything). It happens for 10-15 seconds then stops. It happens more when
my wife dirves than when I do - which is to say she complains about it
happening all the time, and I only experience it occasional ywhen I
drive it.

Does anyone have an idea of what this is? Is it dangerous to dirve?