Water in differential 860

lka

Member
When I first changed the fluids on my new-to-me, long abused 860 what came out of the diff housing was about 40% water, and I had to fish a bunch of gunk out the drain with a wire before it started to flow (initially I thought it was empty). The fluid in the transmission and hydraulic compartments was old but not nearly as contaminated.

The fill cap was screwed down. It has a gasket on it, but its old and rock hard -- I will replace it. Is there another common route for water ingress that I need to look for?

Cheers and thanks.
 
As Olde says. Unless you store it in a heated garage or use it often, it will gather condensation inside the cases and turn your oil milky. I've been changing oils for forty years due to condensation.
I also have a heavy duty brush hog with a 100 HP gear box on it that I have to change nearly every time I get ready to use it from condensation turning the gear oil milky.
 
Did it look like the differential was filled with gear oil? Universal fluid tends to absorb water, giving it a milky appearance, while water and gear oil separate. You might have had as much water in the other compartments as in the diff, but it was mixed up with the fluid.
 


As others have said most of it is from condensation. A few times every year your 860, even sitting in the shed, has water dripping off from it, and at the same time it is running down the interior of the housings into the oil. For its first 15 years it was working hard enough for long enough frequently enough to develop plenty of heat to drive the moisture off. Since then the moisture just accumulates. As MarkB pointed out, modern UTF absorbs water much more readily than plain old 80-90 weight or plain hydraulic oil. You 860 doesn't need UTF. If you put 80/90 and hydraulic oil in it, you simply loosen the drain plugs once or twice a year and let any water run out. This will prevent a lot of rust damage.
 
Thank you much folks, very helpful. It certainly could have been gear oil in the differential, it was nearly pure water for a bit then what came out after the water was pale green and still a bit milky. From the state of the rest of the machine it probably hasn't been changed in a while. I put knock-off HyTran in all three compartments, as I had it on the shelf already and it seemed to be a safe option from looking around the forum.

I did manage to the get the tractor pretty hot the other day (above 200F) but only by covering the radiator with seed debris after mowing overgrown pasture for a few hours. It seems to barely come up to temp otherwise no matter how hard I run it, and it has been quite hot outside recently.
 
Getting the engine up to temperature does not necessarily get the transmission, hydraulics, or rear axle fluids up to temperature. Get a laser thermometer gun and get the temperature of the castings below the oil level to see how hot the fluids inside are getting.
 


You are taking a chance with the UTF. As Sean posted a hot engine does not make the hydraulics hot. Hot hydraulics for ten minutes won't drive the moisture out. Unless you are using it as designed for you should verify that you are working it enough with an IR thermometer. They are cheap.
 
I'm replying to this thread because it is relevant -- the swinging drawbar hangar was severely bent on this 860 tractor and only held onto the differential by one (the top right) of the four mounting bolts. I removed it to straighten the bracket and track down replacement fasteners and noticed that with the bolt out I got a pretty steady drip of hydraulic fluid from that bolt hole on the rear of the differential when the tractor is running.

I'm assuming the hole is supposed to be blind and somebody drilled it out in the past to allow it to communicate with the inside of the diff? If not it does explain some of the water in the differential because the other three holes probably haven't had fasteners in them in 20 years.
 
(quoted from post at 11:47:28 09/07/22) I'm replying to this thread because it is relevant -- the swinging drawbar hangar was severely bent on this 860 tractor and only held onto the differential by one (the top right) of the four mounting bolts. I removed it to straighten the bracket and track down replacement fasteners and noticed that with the bolt out I got a pretty steady drip of hydraulic fluid from that bolt hole on the rear of the differential when the tractor is running.

I'm assuming the hole is supposed to be blind and somebody drilled it out in the past to allow it to communicate with the inside of the diff? If not it does explain some of the water in the differential because the other three holes probably haven't had fasteners in them in 20 years.


ika, you are tough to convince, LOL!!!! CONDENSATION!!!! This condition is extremely common with old tractors. NO! the PO DID NOT drive in water over the rear axle!!!! During use the oil in the differential is slowly getting warmer and EXPANDING resulting in slight pressure. WATER CAN NOT PUSH IN against the pressure!! Once the tractor is stopped it will slowly cool and water could be sucked in but only if PARKED in DEEP WATER!!
 
I'm sure the bulk of the water in the differential is from condensation, I am more interested in why gear oil/UTHF leaks from the drawbar bracket bolt which doesn't seem right.
 

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