Air in Tilt/Trim ??

I am hearing a kinda "gurgling" sound when I tilt my engine that I believe is some air in the hydraulics.

Is there a way to fill the system/
I looked and don't see a cap.

Thanks

Cap is on the starboard side trim up and it is on the reservoir. Pop the cap if fluid comes out it's full if not add some and bleed the system. Put a block of wood under the skeg and trim down onto it. Loosen the manual release screw trim up for a count of 5 and down for a count of 5 (motor will not go up or down) do this for 5 cycles and tighten the screw you should be good to go.

Got it.

Will any hydraulic fluid do?
Power steering fluid is common.

Power steering fluid is the choice. It doesn't foam. Like Tranny fluid.