Mitsubishi MM40SR - Final Drive

So, the "3 big bolts" hold everything together, if you undo them the whole final drive with the casing will come loose, and the ball bearings at the front and the back will end up everywhere.
What you would need to do is remove the hydraulic hoses from the back and plug them and the ports on the travel motor, then undo the bolts that hold the travel motor to the frame of the excavator. You should support the drive on the gear side so that it doesn't just drop to the ground. The thing is very very heavy, maybe you can remove the sprocket prior to all this to make it more light.
When you remove the drive from the excavator you can rest it flat with the 3 big bolts looking up, that way when you undo them gravity will keep everything in place. Take off the gears, undo the bolts and then you can remove the big plate. What you find inside is this
together with a bunch of loose ball bearings. Every shaft has four needle bearings, two cylindrical and two conical, and my guess is they are toasted and that's what was making that noise you heard, because if it was the gears you would have damage there and I cannot see any from the picture you posted. but you never know... anyways any damage will be self evident once you get to this point.
If you dig deeper you will find more ball bearings and the duo-cone seal, which most probably also needs to be replaced, and not so difficult to find. From my experience you have to take things part and measure them to find the right replacement, but maybe you can find parts already since you have a serial number, I didn't. But I would still double check with the part in my hand if I were you.
Let us know how you get on,
good luck

Perfect, seems relativly straight forward. I am still a bit hesitant until I at least know where I "MIGHT" find some parts. I have called a few different locations and have yet to find a place that even suggests the possibility of having parts.
Are you able to recommend some places before I bust this thing open and end up not being able to get any parts?

My 2c. If that final drive has run with no oil in the bearings will all be fcuked. No ifs, and, or buts, they will be totally trashed. If you fill with oil now without disassembling all the crud that's in there will mix with the oil and turn into grinding compound that will take out the gears & shafts as well. They appear to have survived in reasonable condition so far. As Clint Eastwood said in that movie many years ago - "Do you feel lucky?" IMHO looking at those photos you should be trembling in fear...….

As Giubu said above, pull the final drive off the machine and stand it up vertical. That way nothing will fall out when you remove the three big bolts (tip: loosen the bolts slightly before removing the final drive from the excavator, it'll make disassembly much easier when you do come to remove them. Only tighten them again when you get the whole unit back on again).
The bearings are probably standard taper roller bearings from SKF or NTN or whatever. They should be available, along with O-rings and Duo-Cone seals, but it's the shafts, gears, etc, that you might well struggle with.

Well, like Nige said above, the thing is probably totally fcuked, so at this point I think it's more important to check what parts you need to replace than to worry about where to source them. Then if you really struggle to find replacement parts, I can talk to a few suppliers here and see what we can find, at the end of the day my machine is way older than yours and still I managed to find parts for it, so in your case it can't be that bad... Still I would need to know certain dimensions and you can only get those if you take it apart. For sure it will be cheaper than replacing the whole thing.
Best of luck

Awesome, thanks guys I truly appreciate all your advice and guidance! I will be heading out Moose hunting in a couple weeks. Might see if I can get this thing torn down before I leave, but I have a lot on my plate at the moment. I will keep you all posted and update you on my progress.

Talk soon!

I did a very quick search and found Final Drive Centre www.finaldrive.eu They list parts that you need plus there is a diagram of your hub. Just where to get parts in Canada or US I have no idea but can recommend these fellers www.travelmotorsdirect.com.au

Before you remove the hub loosen the 3 bolts but don't remove them. They probably will be tight and unless you have an engine stand or some such you will end up swearing like a trooper

Tones said:

I did a very quick search and found Final Drive Centre www.finaldrive.eu They list parts that you need plus there is a diagram of your hub. Just where to get parts in Canada or US I have no idea but can recommend these fellers www.travelmotorsdirect.com.au

Before you remove the hub loosen the 3 bolts but don't remove them. They probably will be tight and unless you have an engine stand or some such you will end up swearing like a trooper

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So just to be clear, losen the 3 big bolts from the HUB side first because they are so damn tight...

Then go to back side, remove hoses from hydraulic motor and the large bolts from that side, so entire assembly will come off... Then herniate a nut while moving the entire assembly indoors where I can then disassemble on a bench easier?

Pretty much.....
But in the grand scheme of things it’s not that big or heavy, maybe 75kg complete. So it shouldn’t be that much of a struggle to move it around. Get another pair of hands to help you with the heavier lifts if you can.

yeah, that sounds about right, you can keep the sprocket on and roll it on the ground if you have to move it far. Or you can disassembly it there and then, piece by piece it's much lighter. Don't forget to plug the hydraulic ports on the motor or you will get tons of crap in it. An impact wrench should do the trick on those bolts.

giubu said:

yeah, that sounds about right, you can keep the sprocket on and roll it on the ground if you have to move it far. Or you can disassembly it there and then, piece by piece it's much lighter. Don't forget to plug the hydraulic ports on the motor or you will get tons of crap in it. An impact wrench should do the trick on those bolts.

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Ya, I figured. I will probably remove the sprocket at the least. I have some plugs for the motor plugs etc... I am pretty sure that this should all go fairly well. Would there be potential for any machining requirements? Or if nothing is broken / completely warn out then its just replacing Bearings/Seals etc?

Fordzilla said:

Ya, I figured. I will probably remove the sprocket at the least. I have some plugs for the motor plugs etc... I am pretty sure that this should all go fairly well. Would there be potential for any machining requirements? Or if nothing is broken / completely warn out then its just replacing Bearings/Seals etc?

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I would hope that it's just a case of bearings & seals if everything else cleans up. You'll just have to keep your fingers crossed.

The numbers I see for the final drive with the travel motor still in place but with the sprocket removed are around 60kg.

Don't forget you are working on a machine that can lift. With the motor hydraulic's caped the rest of machine cam still work