Ok, I have a hard time shifting while moving on say the highway..

1. The problem started after leaving the Wal-Mart parking lot, the problem wasn't there when I pulled in, when I pulled out of the parking lot it started.

2. When cruising I have to use A LOT of force to get the shifter into gear from 1st all the way through 5th. I only have a hard time while moving fast though.

3. If I'm idling the shifter goes through the gears fine, even if I shift each gear at 5 grand it's ok.

4. I checked my tranny fluid, it was low about a quart. I filled it back up and it's peachy. But the problem still remains.

5. The clutch and tranny make NO odd noises at all, the gears don't grind, the tranny doesn't sound scratchy or whinny.

6. Once I pop the shifter into the gear all is fine, no bogging, scrapping, rpm fluctuating, rpm dropping, or increasing.

Does anyone got an idea?! Even a clue?!