Best ATF fluid for an offshore promax

[simpson_3]

I was wondering what everyone used for ATF? My pump currently has ATF fluid in it... at least I think it does. I'm guessing I can't mix/switch over to mercury trim fluid. I plan on replacing the current mercruiser trim pump with a new one so I'll be replacing fluid as well. I've done a little research and found that I should get something that has no detergent in it. I also found that I should find something without gripping agents in it. Is that true? If it doesn't have gripping agents in it, it will flow faster and have less resistance, is this true? What do you guys run?

[LakeFever]

Ive been using synthetic ATF lately. Makes the cylinders move faster in my experience. Hydraulic fluid is pretty much all the same except for additives needed for the seals. When I get a leaker I add Lucas ATF stop leak, works great

[Chaz]

The ATF with the least amount of additives is F type.
Then the one size ~ fits all , for every application is Dexron - Mercon .
The racing powerglides I built , I found that AW32 Hydraulic oil worked the best. I always put a qt. of Dex / Merc. in a 5 gal. pail to give it color .. As stated , the Lucas treatment is a good idea , even for new oil ..

[Glastron1987]

The reason I like having the red color from the Dexron ATF is that it is easier to see upon level checks or when there are leaks. Never thought of mixing it with hydraulic fluid, but sound like a good idea.

Recently some kind of petroleum leak was noticed in the water around my motor and at first I was not sure whether it was gas, oil, grease, or PT fluid. After closer examination in the sun I could see the red color from the PT fluid (Dexron). I wasn't happy about the leak but I was happy about being able to tell where it was coming from.

[Capt.Insane-o]

32 weight........oh

[Chaz]

32 weight........oh

ISO / AW32 = SAE 10 wt.

[Capt.Insane-o]

ISO / AW32 = SAE 10 wt.

What about food grade?

[SS Minnow]

What about food grade?

You had to ask, didn't you?

[Capt.Insane-o]

lol

[FUJIMO]

...last few hundred brand mercury trim pumps i filled from empty, we used dextron 2 or 3 or whatever came next. its red. its oily. its about 15 weight. not a one failed.

[simpson_3]

The ATF with the least amount of additives is F type. Then the one size ~ fits all , for every application is Dexron - Mercon .The racing powerglides I built , I found that AW32 Hydraulic oil worked the best. I always put a qt. of Dex / Merc. in a 5 gal. pail to give it color .. As stated , the Lucas treatment is a good idea , even for new oil ..

I'm going to flush the system with new oil today. It's a mercruiser style pump but it's been giving me some issues. It will trim down fine but when I'm trimming it up it will give me problems. It will trim up fine for a little bit but when it hits the point where it's trimming "out" the pump gets very high pitch and sounds like it's struggling. At that point, it basically refuses to trim up and all it does is let the motor run. It doesn't leakdown at all which makes me to believe that the trim cylinder is good and that their is something messed up in the pump. I'm thinking of swapping from power steering oil to either hydraulic or to motor oil. Not sure what brand of hydraulic oil to run but I'm leaning towards the 5w-20 mobil 1 motor oil. Thoughts? Do you know what may be wrong with my trim?

[LakeFever]

You sure you dont have crud in there blocking things up? I wouldn't be putting engine oil in there either

[simpson_3]

You sure you dont have crud in there blocking things up? I wouldn't be putting engine oil in there either

In every mercury manual I read they all say you can run motor oil. My local mercury dealer runs motor oil in them as well. How should I check if there's crud in there? Should I check the valves on the pump?

[Chaz]

It sounds like it's just low on fluid …

[simpson_3]

It sounds like it's just low on fluid …

It was right in between low and full. I took the valves apart and one came out but the other one wouldn't. I'm guessing that's my problem.