Checking the fluid level in a ZF63A Gear

[Bill Desmarais]

Good morning,

There’s been lots of discussion on this forum and others about “the best practices” on checking fluid levels in marine transmissions.

I have a ZF63A bolted onto the rear end of my 6BTA 370. I changed the fluid and the filter in the gear this past week. There is 257 hrs on both the gear and the 370.

I’ve been using ATF in the gear (as specified in ZF63A spec sheet) since new. This recent fluid/filter change I switched from ATF in the gear to 15w-40w oil, the same oil used in the 370. Makes changing fluids in both the engine and the gear easier using the “same” lubrication fluid.

To drain the gear fluid, I use a piece of 3/8s fuel line attached to a Water Puppy 12v pump. When you take off the filter cap and remove the little doughnut filter in the gear, there is an opening (tube) that the filter sits on.
I insert the 3/8s hose down the tube to the bottom of the gear sump and turn on the pump. Pumps out I’m assuming most all the fluid in no time flat.

After pumping out all the ATF, I poured a “whisker” under the 4 qts. of Rotella T4 15w-40w oil out of the gallon jug. (3.8 qts +-) I screwed in the dipstick all the way and checked the level. I was “over” the full mark on the dipstick as it should be.

I fired up the engine, idled for a bit (I had just changed the oil and filter on the 370) and shifted in and out of gear at the dock a half dozen times and shut the engine off. I was in a rush, picked up the pump, tools etc and left the boat.

I came down a few days later to finish things up. By that time gravity drained all the oil in the gear back to the gear from the gear cooler and oil lines to and from the cooler. I checked the fluid level with the dipstick “resting on the threads” as specified in ZF literature and “Tony” Tips”.

The oil level was about a 1/16th of an inch above the “full mark”. I used a good size plastic syringe and a piece of tubing to suck some oil out of the dipstick opening to get the level just right…about half way between the low and full marks.

I sucked out maybe 4-5 oz.s of oil to get the level correct.

Next ZF63A oil change I’ll use the same procedure but pour back in 3.5 qts. I’ll report back next year if 3.5 qts is the magic number.

For what it’s worth,

Bill D

1 user thanked author for this post.

Tony Athens

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[Bill Desmarais]

Will do…this week !

[Tony Athens]

Bill,

If you get some time, post a small bit on how YOU winterize your engine.. Many of us guys out here have little clue on the simple ways to do it.

Tony

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