power trim

My power trim was low on oil a couple of weeks ago. I just took it out of the water today and again the trim would not go all the way to the top and it made a 'funny' noise rather than topping out when it hit the top. I suppose it's low on oil again but what or how expensive will this get? Do you have to replace the entire trim assembly or can you fix a leak in it?

Just where is the leak.
Mercruiser type system:
plastic oil bowl cracked where the bottom screw goes in.
fittings not tight at pump
fittings at diverter block
trim cylinder seals leaking.
not filling it or bleeding properly leaving a air pocket

Don't know where the leak is. I'll be climbing in there later this week. I was just seeing what all I can find out before getting in the hole.

My moneys on the screw in the bottom or a stress crack in the bowl.
Ed