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Posted by grahamh on 09/30/10 - 5:12 PM

Any mechanics out there?

I need to add some fluid to my 85 Mercury 150hp trim/tilt unit. The service manual calls for ATF type A or AF. I can't seem to find either anywhere.

I purchased some Mercury Power Trim and Steering fluid but it does not look or 'feel' similar to what is in the hydraulics right now. I do not know what is currently in the hydraulics, but it is red and 'oily' feeling. The new Merc product is clear and almost feels 'dry'. Did not seem like a good match.

The internet research I did indicates that Type A is ancient - maybe used from the 40's to the 60's. Seems strange that a 1985 engine would be using this......

Any thoughts?

Thanks
Graham

Posted by PaulBW on 09/30/10 - 6:42 PM

The color of the fluid is meaningless What you already had was most likely Dextron transmission fluid. Any high quality transmission fluid, such as Dextron III would work but I would recommend the manufacturer's fluid. The differences are additives, conditioners, and coloring. Yamaha fluid is clear also.

Posted by grahamh on 10/01/10 - 5:46 AM

The color isnt exactly meaningless. Fluids are colored (artificially) to help mechanics identify the fluid. Red is usually ATF. Clear is usually hydraulic fluid.

The additives can be significantly different. And 'new' is NOT always better when working with an older system. Some of the new additives can actually degrade components not designed to use them.

I agree that what is in there is probably some Dexron (who knows which version!)just because it is the most poplar fluid.

What the manufacturer 'recommends' is no longer available.

What have other Merc owners done?

Posted by grahamh on 10/01/10 - 6:43 AM

Tom-

Thanks for the info. That is exactly what I was looking for.

Follow-up question: I do not know what is currently in the system. I assume adding Dexron II or III would mix fine with whatever is there. (I know it is some sort of ATF)

Thanks
Graham

Posted by PaulBW on 10/01/10 - 7:28 PM

I know what the colors mean. Its just that the color is meaningless as far as properties are concerned. I'm an auto technician and deal in a mindbogling variety of transmission fluids and hydraulic fluids. ATF is a hydraulic oil. Mercedes transmission fluid is clear to amber. There's also blue in a variety of manufactuers, purple in BMW, etc. And there are legitimate fluids that meet the criteria of some of them that are different in color than the original. Yamaha, Mercury, VW, don't make the fluids afterall. Using the manufacturers recommended fluid is always good but some newer transmission fluids such as Dextron IV, V, and VI take care of most preceding fluids such as Mercon, Dextron I, II etc. and therefore would be fine in your 85 trim/tilt. Now, I'm not a boat mechanic, and don't know what the ultra modern trims are using but I'm confident that most older ones would most likely benefit with, lets say Dextron IV compared to the formula used when the unit was manufactured. Just trying to clear my last post up.