I have driven my 97' Accord EX (Auto) for about 6 years now.
Over the last month or so it has done the following.

When I am on the highway traveling at around 70mph, if I try to accelerate faster, the RPM limits to about 5000 and the transmission will not drop into a lower gear.

This also happens if I am getting on the highway and need to accelerate quickly.

It's like the transmission will not drop into lower gear while at high RPMs.

I checked my transmission fluid and it was on the bottom of the checkered area on the dipstick. I refilled it with ATF (Dextron VI). The bottle said it was a good replacement for all previous Dextrons. My Accord service manual says to use Dextron II, so I figured it would be ok.

It still does the same thing though.

Any ideas?

Thanks for your suggestions!