[Chris1529]

I'm with Bill. It sounds like the brake not working properly.

As far as the linkage goes, I like to pull the pan off so I can see the detents as well as feel them.

If it is a racing C-4 from Dynamic, it should already have the vent tapped.

Is this a new transmission or did you run it with another combo? If you have run it before, what else is different? -the bellhousing, converter, spacer plate?.......