Ran Kx-91 with no oil in final drive - is it shot?

I took a flyer and bought a very used ~2000 hour KX-91 from an estate sale that had been sitting for a while. The machine looked a bit beaten up and had bit of slack in it but overall it worked well.

After I brought it home I noticed the left track seemed to be a bit weaker than the right at times, and short story is the final drive had absolutely no oil in it and was just full of a hardened sludge. The gears were bone dry. I only drove the machine for a few minutes like this, and have no clue if the machine was operated like this for a long time beforehand, but clearly it was a long-ish problem given the hard sludge build up.

I realize the final drive is likely shot for the long run, but even with the sludge and no oil you could barely tell if there was an issue when driving it. So my question is, given I will barely be putting any hours on the machine (perhaps 100 hours over the next few years), is there a shot I can just clean things out, put the plate back on, and fill it up with oil and call it a day? Or am I wasting time and/or risking catastrophic failure and therefore should just buy a new final drive?

I've attached a picture of the sludge and also the gears (note they were dry when we removed the plate - the liquid is from me starting to clean things out).

The only other relevant thing was that the face plate was partially pushed out before I removed it, so clearly something was causing pressure to build behind it. The two small pins that were holding it on to the unit had sheared off.

It absolutely won't hurt to try it. I would not hesitate to clean and fill it with new oil, and the other side too.

If it's just a hobby/property machine just put that cover on, fill it up with diesel and let it sit for a while, run it a lil with no load on it then wash it all out with brakeclean and fill it up.

Thanks for the replies. I'll probably give it a go just putting it back together as-is as it seems like it won't hurt to try.

Two more questions: 1) If it goes bad what are the odds it fails catastrophically and I'm stuck vs being able to limp to the barn? and 2) Any observations from the attached pics?

With a catastrophic failure it will lock solid. By removing the bolts on the sprockets and letting the sprockets slip on the hubs it's easy to tow the machine home for repairs.

It takes a little coordination, but you can usually limp a 1 track hoe.

Run it and see. If you want, catch most of the crud, dissolve in diesel to rinse clean, and see what kind of metal is in the debris. You should be able to see the wear pattern in the gears also. Doesn't look that bad, as long as the bearings are smooth, and the gears are uniformly worn, then accelerated wear is not that big an issue. I think I can see the wear on the big planet gears, but the little sun gear looks good, that's the beauty of the planetary gear system, they can share the load. Most of the reason you can't get a manual transmission anymore.

Run it with cheap motor oil or the infamous "303", drain it after every time you track for a while, until it comes clean enough for your likes. OR, lift that track and run that track for twenty minutes, drain the flushing oil, repeat.

What terex herder said. I had one rental mini toss a track and the rental guy showed up to pick it up, and I walked it up on the trailer with one track and the bucket. It is totally doable.
I have walked more than one out of a terrible mudhole and drug the track out with me to put it back on on dry ( er) ground.

I agree with everyone- wash it out and fill it with 'erl' .

My only concern is what was all that hard pack sludge? I'd never guess any oil or grease would ever get that caked up so curious what was in there. Is the sludge gritty like dirt? If so, I'd try and find how it all got in and prevent from coming in again. Also, what's in the other side?

I assumed that first pic was from the outside, but why would you post it then? Obviously that's dirt, and it needs to be fixed to keep it out like LCA says, and keep the oil in, or at least keep the dirt out and keep grease in.

LCA078 said:

I agree with everyone- wash it out and fill it with 'erl' .

My only concern is what was all that hard pack sludge? I'd never guess any oil or grease would ever get that caked up so curious what was in there. Is the sludge gritty like dirt? If so, I'd try and find how it all got in and prevent from coming in again. Also, what's in the other side?

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I have no idea what the sludge was, but it was inside the gearbox and was part of what seemed to be pushing out the cover plate.

That might be dirt that infiltrated through the seal that let the oil out.

skyking1 said:

That might be dirt that infiltrated through the seal that let the oil out.

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Hmmm- you're probably right. I guess if the seals are that shot, what's the chances of it actually holding any liquid lube? Wondering if a grease or such would be better. I've seen corn head grease mentioned many times on the ag forums as a fix for leaky gear boxes.

Still wondering finding and fixing that bad seal to prevent more contamination is needed.

I think the gear grease leaked out long before the dirt started coming in. If you fill it up, it will leak down to the shaft level quickly. Then you can see what is what.

skyking1 said:

I think the gear grease leaked out long before the dirt started coming in. If you fill it up, it will leak down to the shaft level quickly. Then you can see what is what.

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That would imply this thing has been in a bad spot for a while - how optimistic are you that things will hold up once I put it all back together?

That's like asking a doctor how long my heart is going to last.
Put oil in it and use it. See how long it stays in there.

Every hour you get to use it with the current drive is an hour you don't have to worry about it. Your hoe is not an airplane or NASCAR car or swingy-loopy amusement park ride where failure of an item can be catastrophic to our lives. Just kinda saying like SkyKing did and have fun with it until you can't.

I mean worse case when it goes you pick it up yank the track and change it where it is or have a field mechanic do it if you don't want to limp it somewhere. But I've had them go a long time after they're cleaned out if the seals hold, put good gear oil in it after you flush is and run it.

JLarson said:

I mean worse case when it goes you pick it up yank the track and change it where it is or have a field mechanic do it if you don't want to limp it somewhere. But I've had them go a long time after they're cleaned out if the seals hold, put good gear oil in it after you flush is and run it.

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How complicated is it to change the drive motor in the field? Is it something someone who is modestly handy could do themselves? The unit will not be leaving my properties so that is not a bad option.

Ponyslayer said:

How complicated is it to change the drive motor in the field? Is it something someone who is modestly handy could do themselves?

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I don't know your machine but I suspect the answer to your question is changing a drive is fairly straightforward. But I also recommend you answer your own question but doing all the prep work now that you'll need to actually pull the drive in a field environment. Remove the necessary covers, ensure all is cleaned out, and take a good look. This will give you a good idea of what you'll be in store for when you do decide to pull it. Also, loosen each bolt/nut that you'll need to do to remove the drive but don't actually take out the drive. Better yet, remove each bolt/nut individually, clean the threads and apply anti-seize on them so when you do have to pull it, you're not fighting them in the mud/cold/rain. I wouldn't unloosen any hydraulic lines, but I'd ensure you know what wrenches you need based on your access to the fittings.

Same thing with your sprocket. Break/clean those bolts so if you need to free-wheel that side, you're not busting knuckles trying to get them free when that side is wedged up next to a rock/tree (I don't know why but equipment knows when to break at the worst, most painful moment). Lastly, look around for a replacement drive so you know your sources- this may be your biggest source of downtime.

I don't know what's needed to loosen/remove the track but I'm sure there is a lot more hints and tricks from the folks who had to do this for real.

Oh... and get a manual