Flushing out Contaminated Gear Oil

[shopboy]

Howdy,

I'm in the process of resealing my 79 I Drive.

Upon removal this fall, I noticed water contamination in the oil.

I drained and replaced the oil.

The new stuff I put in is still nasty and contaminated from the remnants of the old stuff.

Is there a recommended way to be drain/flush/push all of the old moisture out before I put new oil in?

Should I just leave it open to drain for many days?

Thanks for the advice..

 

[dbkerley]

Re: Flushing out Contaminated Gear Oil

I'm sure a tech will be along with better advice soon. Obviously you didn't tear it down to repair the problem or it would have been cleaned before reassembly. Otherwise leave it open until fully drained. Then I flush with a good parts cleaner by refilling with the cleaner and rolling it through for a few minute before draining again. Then I refill with gear oil, run it through a little while and drain again. Refill and seal. Recheck after it gets wet to be sure the seals are holding. I always fill from the bottom. This works on other gearcases and should work on a lower unit as well. I use the process more for PM than after a repair.

 

[dbkerley]

Re: Flushing out Contaminated Gear Oil

Also be careful of the cleaner you choose. Some can cause the seals to soften and swell.

 

[shopboy]

Re: Flushing out Contaminated Gear Oil

I did Not tear it down. Just replaced the driveshaft yoke seal.

any recommendation on a brand of parts cleaner that wont eat up my seals?

thanks..

 

[dbkerley]

Re: Flushing out Contaminated Gear Oil

I think the stuff we use comes from Envirosan and is around $160 for 5 gallons. Some B12 Chemdip might be better in your case. Check with your local auto parts store and read all the info carefully. It matters what kind of rubber or nylon your seals are made of. I don't want to make a specific recommendation as I've never done any of my boats that way.