I noticed that during hard drives my tranny dipstick pops out for some reason. What causes this?

 

When you did the converter did you re-bolt it to the bellhousing?
If not then when the motor/trans is torqued it could pop out.

 

He might be talking about the dipstick itself, not the tube.

Mine will do it from time to time. I think that it might have to do with pressure build-up in the transmission that has to escape somewhere.

My trans is stock, and my converter is stock. To my knowledge they've never been out of the car.

 

Oh, if that is the case the check the vent on the top of the tranny, it can get clogged with gunk under the car and also if the tranny has ever been removed then the vent tube could have been kinked closed.