WTH does this mean?!

[73k5blazer]

So I'm taking a little trip in my K5, it's got 6000mi on it since I "built" it. (aka, got it running, again)
So about, oh, 1999 I rebuilt the transmission (SM465), transfer case(NP205), and axles. Installed the Detroit in the 14bff and the ARB in the front(Dana 44). I bought a 5 gallon pail of Exxon Mobil 75w90 gear oil (mineral based). Filled everything up. Over the years of "building" I would rotate stuff occasionally just to move that fluid around in there.
Got it running this past spring, put 6k on it. SInce I'm taking a trip I decide it's time to get rid of the stuff I put in there 13 years ago and put some Mobil 1 Synthetic 75w90 in there.
I drain the transmission, it's a super light brown. Almost creamy white.
Transfer case looks ok, a touch dirty, but ok.
Rear axle, perfect.
Front axle, perfect.

WHat's up with the light brown in the SM465? When I drained it, I though all the rest of the stuff would be like it, but the rest looks more or less like I expected. If it was an outboard motor, I'd say coolant got into the gear oil, but, the SM465 doesn't even come near coolant. Really makes me wonder.

I actually still had the rest of that exxon stuff, so I popped the shifter and poured the rest through there open drain to kinda flush it all out. Let it sit overnight draining then filled it back up with Mobil 1.

 

[cybrfire]

Possibly condensation?

 

[dyeager535]

Condensation would be my guess. I would think with use, it would be gone. My trans fluid definitely heats up with some spirited hill climbing.

 

[73k5blazer]

You really think simple condensation would cause all the fluid to turn that way? It hadn't been operated in 2-3 days.
It seriously reminded me of draining an outboard that the coolant leaked into. It wasn't just a smidge cloudy or something, it was very solid super light brown/off-white, all of it.
Condensation would make me happy, it did sit for quite some time and it gets cold, and warm, and hot, and cold.

 

[dyeager535]

Nothing else can contaminate it, as you said, I agree with that.

If condensation is a possibility, I'd run with that idea. Kind of odd it happened only in the trans, but then again, the axles (at least the rear) probably see a lot more heat in a shorter period of time.

Synthetics are *supposedly* better at combating problems from condensation getting into the fluid, but I'm not certain that is entirely true anymore. Technology has improved even dino oil, what was true 10 years ago may not be true anymore.

My truck sits for months on end, but I've never noticed what you describe. Then again, I don't even look at the trans fluid but once a year, if that. If I put synthetic in the transmission, it would probably outlast me.

 

[Fordum]

How long had it been sitting before you drained it? In other words, did you run it to mix things up and then drain it?

What you are describing sure sounds like water in the oil. If there is a lot of it, and it sits for a while, you will get water out first.
On my old Jeep, it was normal to get about a pint of nice clear water out of the front and rear end every year.
Transmission only produced water if it had been a really wet hunting season with stream crossings that came over the transmission hump in the cab.

But, If I drained it after a drive, the water would be stirred up and come out white and milky like you described.
Of course, a small amount of water will not settle out quickly.

As to how it got in there, not sure. Condensation is certainly possible, even though it seems like it should, a transmission will not boil out a lot of water unless you really get it smoking.

Other than that, its hard to say. It would have to be something unusual.
A vent tube that was facing up and got rained in, open floorboard and a spilled big gulp, maybe even water in the oil you put in.
If you filled it from an opened container, some water might have gotten in while it was sitting around.
It would not be milky out of the can, the water would be sitting on the bottom and you might not see it when you poured it in.

Tis a puzzle......

 

[xenomarine]

I had the same thing come out of the sm465 I bought from a crawler. The thing tipped over in my garage and spilled about a cup of fluid which was opaque(I think that's the right word..), light brown, and creamy looking. Didn't bother to clean it up as I was out of speedi dry at the time. Returned the next day, and the puddle looked like fresh gear oil. I'm willing to bet it was water contamination. Let it sit and the water will likely evaporate out.

 

[454Sub]

Condensation is my guess. Thats why your supposed to warm it all the way up to dry out all that stuff that can accumulate over time.

 

[73k5blazer]

I racked my head on this one for a while.
It went like this;
Started build of this truck in :gulp: 1998.
Built axles,t-case,tranny in 1999/2000 ish.
I filled them all up, with the same fluid from the same 5 gallon bucket of 80w90 at the same time.
I did not finish build until earlier this spring, 2012.Basically all it got for the 10-12 years was me taking my hand and turning the Sm465 input. THe axles got some movement as I would tow it from my old house to new, move it around in and out of the garage, etc. And, the only item with bad fluid was the Sm465, the t-case was fine, axles fines.

Anyway, the only fluid that was like this was the SM65.

I never installed the stick, I had a rag in the hole, but it was old, wet, nasty over time. When I towed it from the old house to my new house, I didn't have the garage ready for it and it sat outside for 2-3 days .It poured rain one of these days. I was out of town on business and my wife called me and asked me if she should attempt to cover my K5 up. It didn't have a windshield or top, and water was pouring in. I do remember it was sitting under a weird gutter half broke out of a lean-to, and I know that spot on that gutter that leaked, gushed water, which I recollect would have been sitting right about over where the K5 was parked at that time.

I think the combination of a huge, direct stream of water, a half-a$$ cover on the SM465 hole it took on alot of water at that time.

How's that for CSI?!

Thanks for all the responses, they prompted me to really think about it. Why, why only the one, why!!!!!!!

 

[blazin_blazer]

so how hard was it to rebuild the 465/205? any special tools ? did you buy a kit for parts or ???