Water in transmission oil

[dpickett]

I changed my transmission oil and found that it's milky (strawberry milkshake anyone?). I read as much on this forum and others to see how the water could be getting in. So far I've seen suggestions that it could be three possible issues:
1) the transmission oil cooler.
2) On postings about milky v drive oil, people suggested it could be some o-rings that may be the problem.
3) Taking in a bunch of water, could lead to water coming in a breather tube.

Are there other possible sources of the problem? Anyone know how to diagnose where the problem is at? The transmission oil cooler is $450, so I don't want to start with just replacing parts (at least not that one) unless I know what's causing the problem.

[boatwakes]

99% of the time we see it from the oil cooler. You can remove the old one and pressure test it to confirm but flush and flush and flush the fluid in the transmission NOW or you'll pay way more than the price of a new cooler for a new or rebuilt gear. Boat year, engine and transmission configuration please.

[dpickett]

Thanks for responding.

Sorry I didn't include the basic info. I have a 2000 21V with a 350 Mag MPI. The transmission is a Velvet Drive Model 10-17-004.

Found a video on YouTube about pressure testing. Are these the correct steps?

1) Remove the oil cooler. Is it easiest to remove the raw water pump first?
2) Plug one of the oil connections.
3) Connect the other oil connection to a air compressor.
4) Put in 10-20 lbs of pressure.
5) Stick it in a tub of water and look for bubbles.
6) If air is leaking, then replace the oil cooler.
7) If air is not leaking, check the...?

To flush, I would suck out the oil with an oil extractor, put in new oil, and run it. Then, repeat three or four times? I'm assuming I'd have to run it to get the oil out of the lines that go to the oil cooler, otherwise I'd still have the contaminated oil in there.

Anything I'm missing?

[boatwakes]

Here's the cooler part number 808029T link for the part https://www.mrcool.us/catalogsearch/result/?q=808029T, $272.

[boatwakes]

Actually, please post the engine serial number and I'll cross reference the cooler.

[dpickett]

It is 0L671100.

[boatwakes]

Ok cool, the link I sent is for the correct trans cooler. They're mounted on the port side of the boat up against the engine block right at the bell housing.

[boatwakes]

You can bypass the cooler and immediately flush by connecting the transmission cooler oil hoses together. Do that ASAP so you mitigate any more rust from forming.

[dpickett]

I'm not seeing the link to the trans cooler. Is there a post that didn't go through?

Are you saying to suck out the oil, put in new oil, connect the hoses together, and run the engine with the hoses connected together (and no oil cooler until I get a new one)?

[lee]

I'm not seeing the link to the trans cooler. Is there a post that didn't go through?

This looks like the right part number based off you serial number.

8M0125847

[dpickett]

Here's the cooler part number 808029T link for the part https://www.mrcool.us/catalogsearch/result/?q=808029T, $272.

Thanks. Weird...this post didn't show up when I looked at the site earlier. Have you had good luck with the Mr. Cool brand? They are quite a bit cheaper than the Mercury OEM stuff.

Any chance you'd be willing to shed some light on the questions I asked about the process of checking the oil cooler and flushing the contaminated oil? Just want to make sure I'm doing it right.

[dpickett]

This looks like the right part number based off you serial number.

8M0125847

This is the fuel cooler, not the transmission oil cooler.

[lee]

DUH!

[boatwakes]

The mr. cool brand products have proven to be a fantastic alternative to OEM across all brands, we've been very happy with them and are able to pass the savings on to the customers too.

As for your flushing questions, my apologies, was on the road for vacation and totally unplugged. But yes, remove the contaminated oil, fill with new, connect the hoses and run the engine. Do that a minimum of 3 times but preferably 5.

[dpickett]

Thanks for the info on Mr. Cool and the way to flush.

I removed the oil cooler and ran the pressure test and found no leaks. I've attached some pics to show the test I ran. Are there other possibilities for how the water got into the transmission? Having too much water in the bilge and having it come in through the breather?

This water has been in the transmission all winter (yeah, I know I'm an idiot for not changing the fluids before parking it for the winter). Is there anything else I should do besides flushing (and praying the tranny isn't rusted solid)?