crossy

Installed my Juice With attitude and pretty happy with it especially considering I copped a good deal for a brand new one through a board member . It does however make me realize now how badly something has to be done to the trans to fully use the new power.
When making a full throttle pass you desperately want the thing to get the next gear to use the torque especially between 3rd & 4th. what am I feeling ?? and is there a cure SHORT OF buy ing a new trans and or converter. the truck only has 4000 miles on it. I'm not afraid to drop the pan, thanx for any help. crossy