I realize that power trim questions are a never ending topic and I apologize for bringing another one to the forum, however I'm totally at a loss. I've read through my manual and various forums on the matter and nothing that has been recommended. So I'll list what's happening and what I've done so far to diagnose and troubleshoot and hopefully there's someone out there that can give me some really good advice or show me where to go in order to possibly rebuild this tilt motor.

Johnson V4 85HP

1) I refilled the power trim reservoir.
2) The power trim will go up but not down.
3) I checked the hydraulic fluid level and it is fine (sits at the bottom of the filler hole)
4) I turned the engine on and off and let it run for several minutes.
5) I manually raised and lowered the engine in order to bleed the hydraulic fluid and move it through the valves.
6) I swapped the electric switches and they are both clean and in good working order. (So please don't tell me to check the switches).
7) The motor still goes up but will not go down. There is power going to it, the servo starts to move it down a fraction of a mm then it starts making this loud high pitched whining sound. It sounds as if there is no fluid in the cylinder responsible for lowering the unit.

So, there's where I'm at. Aside from buying a whole new assembly I'm out of ideas and advice. I'm hoping there's some pros out there that have seen this issue a few dozen times and can give me some clear direction.