No gurgling noise that I can hear. I'll find the manual pressure valve but if it wasn't tight wouldn't be leaking? Last week I topped off the the oil level last week and it was low but when I checked it today it was full.
So the manual pressure release valve was closed tight. I worked it a few times, motor lowered like it should and raises like it should. I guess whats most confusing to me is for the tilt to lower on it's own there would have to be a leak wouldn't there??
The manual release does not drain fluid to the outside. It just causes fluid to bypass the check valve and that allows manual lowering of the motor.
Since the tank seems to be full and you don't hear gurgling, it is more likely that the check valves are clogged, there is sediment in the oil or the valves and springs are shot.
The pump and valve rebuild is complicated and can be expensive once you buy all the parts, It can be chalange to remove the tilt assembly and separate the pump from the whole mechanism
Again, I suggest that you unscrew the relief valve all the way until it comes out and have a look at its seals. Oil will most likely spill out when you take it out.
Reinstall, fill and bleed and see how it goes.
If your motor drops under thrust, you would assume that it will do the same if you hang on it. If the boat is in the water, you can tilt it up a bit and then climb on the cavitation plate to see if the LU drops.
I suppose it is possible that there is an electrical issue that is causing the trim pump to run intermittently.
Youcan also check that by disconnecting one of the tilt motor leads under the cowling at the tilt relay. Of course the motor should be in that somewhat tilted position before you disable the tilt pump. Go for a ride and see if the motor drops. If it doesn't, you may have a bad relay, wiring, cowl switch ( can be disconnected easily) or control trim switch.