Transfer case fluid particulate

I went to fill the transfer case back up in the Alpha and when I went to put thread sealant on the drain plug some residual fluid came out. I noticed it looked milky in color so I pulled the drain pan out from under the Alpha and took a look at it:



A bit hard to tell in that pic, but it's seemingly a ton of very, very fine aluminum particles (assuming it such since it does not cling to a magnet). You can rub the fluid between your fingers and feel nothing. I know that SuperBuick had the transfer case rebuilt just last fall, so I'm wondering if this would be considered normal after such a procedure. Maybe it's the shifter fork wearing in? Before the engine rebuild I had no issues with the transfer case, took it down to Moab and ran a couple trails with it and it performed flawlessly.

Thoughts?

No clue. Just change the fluid every 10k just to be on the safe side lol. It is pretty cheap to keep fresh fluid in the t case.


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I'm confused.... The transfer case is a two half sealed unit you drain it and fill it thru a plug.. The transmission has a pan on it without a drain plug.
If you've dropped a pan it is on the transmission. Fluid is a bit milky looking but ????

Those particulates are more then likely the pads on the shift fork or the fork itself. If we're talking about the transfer case.

Happy Hummer said:

I'm confused.... The transfer case is a two half sealed unit you drain it and fill it thru a plug.. The transmission has a pan on it without a drain plug.
If you've dropped a pan it is on the transmission. Fluid is a bit milky looking but ????

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When I say drain pan I mean the plastic pan I used to catch any fluid in. Maybe that's where you're confused? I certainly didn't pull the transmission pan, that transmission is a freshly reman'd unit from Street Smart.

Happy Hummer said:

Those particulates are more then likely the pads on the shift fork or the fork itself. If we're talking about the transfer case.

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It is the transfer case, and that is what I am hoping is the source of the particulate. I just don't recall seeing anyone else mentioning this. Maybe by the time they drain it next it's already turned brown so it's harder to see the particulate after replacing the fork.

I changed my transfer case fluid after Moab with only about 3000 miles on it and there was a lot of silver. Previous t-case fluid change had over 10,000 miles on it and nearly no silver on it. I had more silver in this fluid change than any other that I can recall.

So, what's my conclusion? Moab was hard on it and there was extra wear and tear. Not an urgent issue at this time but something to be aware of.

Thanks Alex, that makes me feel better. I'll probably take a sample after my trip to Colorado and see how it's looking.

That fluid has water in it. Looks like a latte from Starbucks. It should look red (fresh) or black (old). Chocolate milk is NOT normal. Fine metal dust is normal, and it’s usually very soft debris, so it’s not a reason to freak out just yet. The biggest issue with this fine dust is that it can clog the screen on the fluid pickup pump, and slow the fluid flow to a trickle. This screen is very fine...more like a filter than a screen. If you crack your t-case open for a chain or fork replacement (common service items)...definitely consider replacing or at least cleaning the screen. You can remove the screen, blow it off with aerosol brake clean, and reinstall it. As always, frequent oil changes is the best preventive.

Also make sure your vent hose is connected to the t-case. That much water in the oil points to some serious river crossings, or more likely (gulp)...a flood damaged vehicle. This might also explain the need for your recent transmission replacement. It raises eyebrows for sure. Might want to drain & refill the diffs too just to be safe.

Don’t panic. Just change the fluids. If it’s functioning properly...run it.

I know that SuperBuick had the transfer case rebuilt just last fall, so I'm wondering if this would be considered normal after such a procedure

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Breakin after original assembly / rebuilds typically leaves more "shiny" stuff in the fluid than subsequent changes. Some of the assembly lubes used may even have fine particles in them on purpose.

Every time I've ever drained a transmission or t-case or diff on a vehicle that has never had it done since original assembly (doesn't matter if it has 30K miles or 150K miles), the fluid comes out gross with with "shiny" metallic look to it.

4speedfunk said:

That fluid has water in it. Looks like a latte from Starbucks. It should look red (fresh) or black (old). Chocolate milk is NOT normal. Fine metal dust is normal, and it’s usually very soft debris, so it’s not a reason to freak out just yet. The biggest issue with this fine dust is that it can clog the screen on the fluid pickup pump, and slow the fluid flow to a trickle. This screen is very fine...more like a filter than a screen. If you crack your t-case open for a chain or fork replacement (common service items)...definitely consider replacing or at least cleaning the screen. You can remove the screen, blow it off with aerosol brake clean, and reinstall it. As always, frequent oil changes is the best preventive.

Click to expand...

It's definitely not water, it's just that much aluminum particulate is in there that is making it look like that. I noticed after it sat for a day in the pan that the aluminum had settled down to the bottom and the fluid turned back to it's normal red color (albeit a bit dark, which is to be expected). I stirred it up a bit and it went right back to being that same look/color. I can definitely see why you think it looks like water got in, that was my first thought as well. I had to look pretty closely to see that it was particulate and not water causing the color.

Thanks for the input all, I'll keep an eye on it and change out the fluid after my trip. We'll see how it fares.

Good to hear.