[TheMolarMass]

What are the symptoms of an overfilled manual transmission?

I took the filler plug out, and ATF began to flow from it. Not the drain plug, the filler plug.

[Vortex]

The one thing ive always heard of was seals start to leak. once it drains back down to beneath the fill plug hole, i would think it should be ok if its not acting funny now...

[OzPony]

I heard it can build too much pressure and blow your seals over a period of time..

[stang2_3]

If I were you, I would just take out the fill plug and let it drain until it quits and that will be the correct amount