Case 850B won't move when outside temps are under freezing

[pat80flh]

Howdy guys, new member here. I'm a retired auto mechanic who bought 30 acres in the Allegany mountains. I bought a used 850B track loader to clean up the property, junk in far, unreachable corners, trail maintenance, some wood cutting. It's worked well until... I wanted to get to a muddy spot, and waited for a freezing day, got the machine started, won't move, forward or back. Doesn't engage. Tried the hi/low, same. No clunk, no strain, you can hear a slight change in idle, trans pressure is in the green on gauge. Wait until it warms up, fires up and works normally. Trans oil was slightly low, barely touching bottom of stick.
My theory was that water had gotten into the oil and was freezing, blocking a passage or line. I dumped the oil yesterday, got the pressure filter and suction screen out. Fluid was a little cloudy, and filter looks fairly new. The housing for the suction screen had a bit of debris in it, one small piece of what looked like a fiber clutch plate, and also part of what looks like a rubber lip seal, again very small. But enough to introduce a new theory, a clutch piston seal, starting to disintegrate, letting fluid flow by until everything warms up enough to work.
I'll be headed to town today to see if I can track down fluid and filter. See if it helps. I've been doing some heavy reading of shop manual. I spent quite a few years as an automotive transmission rebuilder so I don't think a trans overhaul would be out of my league, removing it might be. I'm 66 and the body is pretty worn.
I'm new to heavy equipment and appreciate any advice or comments.

 

[Vetech63]

There should be a transmission pressure gauge on the dash. If it works, what is it showing in neutral, forward, reverse, at all speeds? Does it stay steady or fluctuate? What are those readings when the oil is cold and hot?

There is a driveline under the floor panel where your feet are. Does it stop when you put the machine in gear? It should spin when in neutral.

 

[Oxbow]

No chance you are frozen to the ground is there, or mud frozen in the sprockets and idlers?

Unlikely because you said it doesn't load up the engine, but I thought I would throw that out there.

 

[pat80flh]

Thanks guy, for your replies. I'm sure it wasn't frozen to the ground, I put the wife in the cab, not even a hint of movement from the sprocket.
I haven't paid much attention to the pressure gauge, when the machine was failing, the gauge was well in the green at idle, about 2/3 up the dial, halfway into the green.(no numbers). It stays steady. Dips very slightly, then returns to normal, when engaging reverse or forward, tracks disengaged. I have the left floor plate off now.
I managed to get the fluid and filter changed, NAPA crossed the filter number and the local farm store had fluid. Cleaned the suction screen and housing out and put it all back together. I didn't hurt it, works as before. It's damn near 70 here in the Southern Tier of NY, and muddy. I put her back under the dirt floor lean-to. Won't be until tomorrow night before we see freezing weather again, so that'll be the test.
Heavy equipment guys have my respect, all that climbing and crawling hurts.

 

[Mcrafty1]

When you get to be our age(s) I'm 68....sometimes it's going to be better to just hire the mechanic work done.... We ain't kids anymore. Just saying. I know it's a money thing but at what point are we saving money If we are shortening our lives. I hope you figure this out without too much trouble. Good luck.

 

[pat80flh]

So.... new oil and filter failed ti fix this problem. I had the left floor plate off, the driveshaft turns in neutral and both tracks in neutral. Engaging forward or reverse stops the drive shaft. Fluid pressure in the green, slight dip when forward or reverse selected but only a little, the right back to normal, about 2/3 up the dial, halfway into the green. It takes less than a second for the driveshaft to stop turning, forward or reverse.
I had someone advance the theory that there may be water in the final drives freezing. I haven't checked those yet. I'm sure they're ready to be serviced . At this point I'd love to screw a pressure gauge in while it's failing, but looks like warm weather ahead.

 

[Welder Dave]

Sounds like there could be water in a compartment. Similar to a skid steer with water in the chain cases. When it's freezing weather, I always lift the track off the ground with the bucket to make sure they aren't frozen. If they're free the machine usually moves for just a bit when lifted. I also have a backhoe and can lift the whole machine up. When it's cold it takes a while to warm up and needs a lot more throttle to get moving. After half an hour or so it moves a lot easier with less throttle to get moving. Mud in the sprockets and undercarriage can freeze too.