trans fluid or trim fluid

[steplift20]

in my manuel it says you can use transmission fluid if you dont have power trim fluid, The reason im asking is that i have a leak in my 150 mercury out board but i cant locate it, sounds funny but its the truth, so instead of buying trim fluid whitch is more money can i use trans fluid, is it the same, anybody know? thanks
my mechanic said if i hold it to the up position and hold it there it puts the system on with the greatest preasure so i should be able to find it then, im going to try it as soon as i get the batterys in it.I live in the n.e. new jersey so the weather isnt that good yet to work on it but very soon as soon as i get my house in order [thats what my wife said]