1996 40hp Merc-New Tilt/Trim Pump doesn't pump

[BoomerangFishingCharters]

Tilt/Trim Switch on shift lever shorted out and burned up old pump. Installed new dbelectrical pump, filled with new fluid to bottom of plug hole. Battery fully charged. Tilt/Trim Motor seems to be functioning properly. Motor runs but will not raise/lower motor. There are distinct changes to the rpm and motor pitch changes like it is trying to build pressure. Removed fill plug and oil blew everywhere, high pressure inside the motor. Refilled motor, energized up and down until the motor became warm.
Still no luck. Any suggestions?