cat d6d 4x series: moisture found in trans fluid even after changing. slight milky

[Mountainmover]

hello,


so i have a super nice and tight d6d. everything works lovely. it sat a few years due to economic decline.
i got it ready for a job, new fluids, new batteries, new roller, this and that....
i put in to-4 30 weight trans hyd fluid in the transmission. and new filters due to it sitting and i was seeing a slight milky texture in trans. i assumed it was condensation from sitting.

so i a running this machine and it is working lovely. nothing is heating up. flawless.
i check the tranny fluid....it seems to have a milky texture still.

what could cause this?
how does the trans cooler work in relationship to the radiator? can coolant be getting in a cracked tube in cooler and entering the trans fluid?
how is the trans cooling system laid out in this machine? does anyone have a page to view from the service manual? any ideas?
thanks!

 

[td25c]

Check the coolant in the radiator , is it clear / clean ? Don't know about the D 6 but my IH td25 dozer uses what I call a cartridge type transmission cooler . Cooler is bolted to the side of the engine & ties in to the cooling system . Couple hydraulic lines bring the oil from the transmission .

Anyhow , I fired it up one morning and while letting it warm up I noticed coolant coming out the overflow tube . Shut the engine down & pulled the radiator cap ....... Instant milk shake in the radiator tank .

Pulled the cooler & put about 25 psi air on the oil side found one ruptured tube , soldered it up & was back in action .

 

[Mobiltech]

The trans cooler can leak coolant into the trans but you should be having to add coolant if it is.
If you had moisture in the trans from sitting or condensation you would not get it all out by a single oil change. There is a lot of oil that remains in the system when you drain it.
I guess the question is are you loosing coolant? If it is coolant in the oil if you leave it parked without running for a couple days you might be able to crack the trans drain plug loose and back it out until it starts dripping . If it drips clear water it's a condensation issue. If it drips green coolant you know what's happening.

 

[Mountainmover]

milky

The trans cooler can leak coolant into the trans but you should be having to add coolant if it is.
If you had moisture in the trans from sitting or condensation you would not get it all out by a single oil change. There is a lot of oil that remains in the system when you drain it.
I guess the question is are you loosing coolant? If it is coolant in the oil if you leave it parked without running for a couple days you might be able to crack the trans drain plug loose and back it out until it starts dripping . If it drips clear water it's a condensation issue. If it drips green coolant you know what's happening.

you could be right.
when i changed the filter up beside the engine, there was some milky oil still under filter. i am sure the lines still had milky fluid. i didnt even get to pour 25 gallons in the dozer that i should hold after completely draining the trans.

so the trans cooler does have coolant passing by it?

it is a white milky. not a green coolant milky. i havent lost any coolant that i can see. coolant looks green but i will recheck.

so the water will separate to the bottom of trans and i can let that drip out after sitting. hmmm...

is it normal for one that has sat a year to get condensation in it?

thanks!

 

[Delmer]

is it normal for one that has sat a year to get condensation in it?

Not that much water. There's thousands of old tractors that haven't been run or had a fluid change in years/decades, they don't turn milky unless rainwater is getting in.

You might have been able to get some water to drain out at first, then run it to stir up the fluid and see if you get any more out after it sits.

The other possibility is the oil is getting aerated. Drip some on a hot piece of steel, it will sizzle if there's water in it, and just smoke like clean oil if there's air in it.

 

[Mountainmover]

aerated

Not that much water. There's thousands of old tractors that haven't been run or had a fluid change in years/decades, they don't turn milky unless rainwater is getting in.

You might have been able to get some water to drain out at first, then run it to stir up the fluid and see if you get any more out after it sits.

The other possibility is the oil is getting aerated. Drip some on a hot piece of steel, it will sizzle if there's water in it, and just smoke like clean oil if there's air in it.

thanks.
the oil does seem foamy. i am pretty sure i did not get all the moisture out of the lines when i did the fluid change.

what would be causing the aeration you think? is that bad?
it shifts and runs flawlessly.

 

[Nige]

Aeration is usually caused by an air leak in the suction side of the system, often an old o-ring in a joint somewhere that's dried up and cracked.

 

[Multiracer]

It is usually the oil that travels into the radiator not vise versa from any failed cooler. The oil pressure from a trans or an engine will overcome any pressure created in a cooling system. Have you run the machine hard to really heat the trans up since the change ? You may evaporate some off with a good run.

 

[Nige]

A cooler leak will pass oil into the radiator when the machine is running, and if the machine is stopped hot the pressure in the cooling system will push a certain amount of coolant into the oil until the pressure in the cooling system drops to zero.

 

[Mobiltech]

With trans cooler leaks I find you get more coolant in the oil then oil in the coolant because the trans oil cooler only has trans lube pressure on it which can be under 10 psi. An engine oil cooler runs higher pressure on the oil side and will push oil into the rad.
If it's water rather than coolant in the trans it is probably from rain entering rather then just condensation. If the top steering clutch covers have any leaks and water is allowed to sit on top of the case it will leak into the trans.

 

[Mountainmover]

Aeration or rainwater maybe

With trans cooler leaks I find you get more coolant in the oil then oil in the coolant because the trans oil cooler only has trans lube pressure on it which can be under 10 psi. An engine oil cooler runs higher pressure on the oil side and will push oil into the rad.
If it's water rather than coolant in the trans it is probably from rain entering rather then just condensation. If the top steering clutch covers have any leaks and water is allowed to sit on top of the case it will leak into the trans.

Thanks for the help so far guys.
Dang. It is possible that rainwater is getting around the steering clutch covers.
I'm thinking I didn't get all the milky oil out when I changed it cause the lines and such took up most of the 4 gallons that it didn't need after draining it and replacing it.
It is supposed to hold 25 gallons and it only held like 20 or 21 ish .
I drained it from the big plug under the tranny.
We had the transmission totally rebuilt 500-1000 hours ago.

So if it's aerating from the suction side....how in the world do I trace that down?

Oh lord, I need a service manual at a good deal.

 

[John C.]

Does this machine have a winch? If so drain the fluid out of it. They always leak rain water in which fills it up and the water displaces the oil into the transmission until the water is all that's left. It then also fills the transmission.

 

[Mountainmover]

No winch

Does this machine have a winch? If so drain the fluid out of it. They always leak rain water in which fills it up and the water displaces the oil into the transmission until the water is all that's left. It then also fills the transmission.

Hey.
This Dozer does not have a winch. It has rippers.
But I understand what you are saying. I think d6c had a big issue with that right?

If this is caused by aeration... Will it hurt it to just leave it alone? How do I find the leak?

If it's caused by the cooler... Oh lord.

Rainwater? Well damn...... Off with the seat and toolboxes and floorboard and fuel tank right?

 

[Mobiltech]

If it is a rainwater leak you can maybe see it from the back looking under the fuel tank or from under the seat. Look for any broken or missing bolts on top of the case anywhere. Check the breathers are there and not broken. There should be one screwed into the clutch covers.

 

[Nige]

Start by eliminating the easier possibilities first. As Mobiltech says you can likely get a reasonable look at the clutch covers from behind the tractor. Each cover should have a breather in it and should have all the bolts in place and they should at least appear to be tight. If you have any doubt whatsoever then lift the floor plate, clean everything up, make sure the cover gaskets are in good condition, all bolts tight, and the breathers are clean. It's the only way to eliminate the possibility. If you do end up lifting the floor plate and find it is NOT the clutch covers then DON'T PUT IT BACK until you have completed Step 2 below because you will need the same floor plate up for that.

Second possibility would be an air leak in the suction side of the oil system, often caused by an old dried-up O-ring in a flange somewhere. There are not many joints that can leak up to and including the pump from where the oil is sucked out of the transmission case. If you definitively eliminate water entry via the clutch covers then post back here and I'll post a schematic of the transmission hydraulic system showing all the joints to check, speaking from memory I think it will be only 2 or 3.

 

[old-iron-habit]

Aeration is usually caused by an air leak in the suction side of the system, often an old o-ring in a joint somewhere that's dried up and cracked.

Would an oil analysis tell if it was air, rain water, or cooling water? That may eliminate many possibilities. May also tell if other damage has started.

 

[Nige]

An oil analysis might detect the presence of glycol if it was a cooler failure. If the coolant in the radiator is of very low strength the analysis probably won't pick up glycol, but it might pick up either sodium or potassium, both of which are additives in antifreeze/coolant. Not any lead-tin faced bearings in a transmission for the coolant to get at thought, not like an engine ............

 

[Mountainmover]

Thanks guys.

So what is the best process for doing an oil analysis? I haven't performed one in a few years due to economic downturn in economy in the southeast USA.
I used to have this brass looking thing with a black pull handle for an oil sample. Just put a hose down in the fill tube and pull some fluid and put in a little plastic white bottle? Write my inquiry on the card and mail to CAT Oil analysis???
Any idea of cost?

If this is an aeration problem...do i NEED to fix it? does it cause harm? IF I need to fix it...how do I pinpoint an aeration cause and leak detection in a line? Smoke? lol.

Thanks Nige and ole-iron-habit etc....
Much appreciated!

 

[Delmer]

Buy the kit at Cat, $11 each or $100 something for a ten pack that includes the tubing. That includes postage and testing! You want to either drain the oil from a line while it's running, or suck it directly into the bottle with a clean piece of tubing (your vacuum pump and oil suction hose both go into the bottle so you don't contaminate the oil with your pump or old tubing).

I mentioned aeration because "milky" is hard to define, you might be able to tell by looking at it whether it's water or air, or try the drip on a hot manifold test, or put a quart in a glass jar and let it sit overnight, or...

If it's aeration it will cause problems EVENTUALLY, a little bit of air is normal, a little water makes the oil's antifoaming additives less effective. Maybe you could use it to see what happens, hopefully you have a transmission pressure and temp gauges that work?

 

[Mountainmover]

i am pretty sure the coolant is getting in oil now. overflowing dipstick on occasion.

Buy the kit at Cat, $11 each or $100 something for a ten pack that includes the tubing. That includes postage and testing! You want to either drain the oil from a line while it's running, or suck it directly into the bottle with a clean piece of tubing (your vacuum pump and oil suction hose both go into the bottle so you don't contaminate the oil with your pump or old tubing).

I mentioned aeration because "milky" is hard to define, you might be able to tell by looking at it whether it's water or air, or try the drip on a hot manifold test, or put a quart in a glass jar and let it sit overnight, or...

If it's aeration it will cause problems EVENTUALLY, a little bit of air is normal, a little water makes the oil's antifoaming additives less effective. Maybe you could use it to see what happens, hopefully you have a transmission pressure and temp gauges that work?

thanks for the info about the oil sample. i may do that at a later time.

so, the coolant is getting low and the trans fluid is belching out the dipstick sometimes and running down the side. milky. i am pretty sure its the trans cooler.
i dont have a service manual.

so how is this machine laid out? the trans cooler is built into the radiator?
how much to buy a new or should i get it repaired (brazed?).

Do i take the sweeps off the machine...pulls the hardnose around the radiator and the pull the radiator?

is this thing built INTO the radiator or connects to it?
the fins on my radiator have lots of flattening that i have noticed? any good ideas and tips? time? money?
a good source for a cooler or radiator with cooler?
price?

thanks guys