Topping Up Bennett Trim Tab Oil

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Jonah

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Hi all,

Recently stumbled upon the electric motor to my Bennett trim tabs. The oil level looks low. I don't see a fill-spot, so am wondering if I should remove the upper unit to access the lower? Anyone else done this before? I've written to Bennett, but have not yet received a reply.
 

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Look right behind the silver cylinder and you will see a black plastic/rubber plug that can just barely be reached. Remove it and that is the fill port. I use a syringe to add fluid. It's not east but don't separate the top from the bottom.
 
Yep, looking at your pic, the fill is the thing sticking up just on the left side of the pump, remove the cap and use a syringe to add transmission fluid. Sorry if that wasn't a technical description. :shock:
 
On my pump the filler cap is right beside the pump after you remove the clear plastic cover. It is a small round black cap about the size of a nickel. It just lifts out, no threads. I can see yours in the picture right below the red wire.
 
Thanks everyone. Very glad I asked.

Also, the plastic oil well says that I should use automatic transmission fluid. Are they all equally good, or does anyone have advice on the best type to use?
 
Any ATF is fine. Are your trim tabs currently extended? The level will be lower when they are. When filling, tabs need to be retracted. Go to Bennett's website - lot's of info there... direct from the horse's mouth.
 
Use any type of Automatic Transmission Fluid (ATF). Don’t worry about the exact brand or type – it will all work, and can even be mixed. To add fluid, remove the Lexan cover on the HPU, locate the “filler stack” in the left front corner of the reservoir. There is a round plug sealing the filler stack. Remove the plug and add fluid to the full line on the reservoir. Note: Add fluid only with the trim tabs fully retracted (up). If your reservoir does not have a full line, add fluid so the fluid level is about 1 inch below the top of the reservoir with the trim tabs fully retracted (up). Your Bennett Trim Tab system should not need refilling for several seasons.

HPU_ATF_Filling.jpg


Tom McGow
Bennett Marine
 
Thanks again everyone.

I’ll check the tab level first, then fill as you’ve described.

One last question: I have some Mercury "Power Trim & Steering Fluid", which is "for use on most (Mercury) power trim and power steering systems". Is this ok, or is transmission fluid better?

Thanks again.
 
Transmission fluid would be what I would use. Not sure if tilt/trim fluid is compatible with transmission fluid if mixed. Bennett recommends transmission fluid for a reason.
 
Ky Grady said:
Transmission fluid would be what I would use. Not sure if tilt/trim fluid is compatible with transmission fluid if mixed. Bennett recommends transmission fluid for a reason.
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Good call, KY Grady. That's what is in there now. I topped it off about every 5 years. You should be good for awhile. ツ
 
All done. Picked up some automatic transmission fluid at the local shop here in Nassau, and it was more than enough.

Thanks again.
 
I'm after some expert advice! I have a 1990 Seafarer 34' Flybridge Cruiser, fitted with Bennett Trim Tabs. I need to fill the ATF reservoir (only accessible by a contortionist!) but am not sure how to do this. Do I need to unscrew the arched cover to access the front-left filler?20251015_125338.jpg
 
Fill is on your "blind side" of the pump. It's a black plug cap. If you have a camera use it. Look at post#7 above.
 
Hookup1 said:
Fill is on your "blind side" of the pump. It's a black plug cap. If you have a camera use it. Look at post#7 above.
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My problem is that the Bennett instructions on the front of the tank say "Remove black filler plug (located front-left)". So is that the front-left fitting with the hose connected in the picture? And my pump doesn't seem to have a cover, just a strap holding it in place.
 
I have a square cover held on by a single screw on top. Looks like yours is missing. I think you are looking at the front of the unit. See if that black hose on the left comes out (and where does it go?). I think that is your fill. Should be able to pull that hose, stick a screwdriver in it and you should see it in the lower tank.
 
Hookup1 said:
I have a square cover held on by a single screw on top. Looks like yours is missing. I think you are looking at the front of the unit. See if that black hose on the left comes out (and where does it go?). I think that is your fill. Should be able to pull that hose, stick a screwdriver in it and you should see it in the lower tank.
Click to expand...
I'll give it a try.....many thanks. I will let you know if I succeed
 
At one point in time there was a cover.

Grab the other end of that black hose - I suspect it's just snugged/tucked down so as not to possibly collect water. Someone may have put that there to make it a little eaiser to fill.
 
Previous owner may have had a slow leak somewhere and filled it from time to time.
 
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