lower unit oil change question

[dhughes49]

I drained lower unit oil no water came out. Oil was blue but I could see a streak of grayish color as it drained . I put it in a clear glass jar and let it set for a few hours. A thin layer of sediment formed at the bottom of the jar . I see no water. the thin layer seems like a paste texture maybe a 16th of an inch thick . Is this normal ? I need to add this information . Last year I did have water in the unit . I found a old drain plug gasket under the new one I put on , so I pressure tested per the service manual and it passed , so I cleaned out old plug gaskets and installed new. FYI . The question still remains . Is this normal ?

 

[emckelvy]

The sediment might have been residual from when you had water in the gearbox. The new oil would have mixed pretty well by now with any residual that had been clinging to the L/U innards.

Probably the thing to do would be to refill with clean oil, run it a few times, then pull the lower drain plug & do a quick check for contamination.

If the oil comes out clean, I wouldn't worry about it. If you are having issues with water in the L/U, you'll certainly see it then.

HTH.........ed

 

[dhughes49]

Ok thanks I'll do that.

 

[Mi duckdown]

what emckelvy posted. but I would change the drain a vent gaskets any time you do it with NEW

 

[Texasmark]

Agree with the above and I usually kept a supply of washers on hand. My engine used the light blue washer and I got them at the Merc dealer.