304CR Final Drive Alarmist Oil Sampling

[nonprod]

Hello friends,

Maybe y'all can give me your opinions about recourse, in the ugly discoveries in my 304CR Final Drives.

Back story: 2006 machine, NAD04265, 4800 hours, no service history, 'normal' general significant abuse, etc. No travel issues in operation. When I acquired the machine I drained and refilled the FDs, the oil was old, ugly, smelled of cancer, etc, but I didn't find gear shrapnel or other grave items. I changed it to a fancy Redline 75W90, probably should've just put in the Cat Oil, but then I ran for 75 hours, and then sampled both drives, with attention to (sample) cleanliness, and sent them to the Peterson Lab in Eugene.

The come back with a number of notes:

1) Both drives quite elevated Iron, Calcium, Aluminum and Silicon, and they mention Chrome in the left.
2) Metal Flakes, they say non-magnetic more in the Right
3) Water (condensation) in the Left

The Cat note on the Left:
TRACE WATER DETECTED, APPEARS TO BE CONDENSATION. SILICON AND ALUMINUM INDICATE A HIGH DEGREE OF
DIRT CONTAMINATION. IRON AND CHROME ARE ELEVATED SUGGESTING INCREASED GEAR AND BEARING WEAR DUE
TO DIRT. CHECK FOR DIRT PACKING AROUND FINAL DRIVE AND INSPECT SEALS FOR ANY DAMAGE. CHANGE OIL AND
FLUSH COMPARTMENT TO REMOVE CONTAMINANTS. RESAMPLE IN 50 HRS.

And on the Right:
MORE SAMPLE HISTORY NEEDED TO ESTABLISH A NORMAL WEAR TREND. VISCOSITY IS HIGH. SILICON AND ALUMINUM (
TYPICALLY DIRT) LEVELS APPEAR HIGH AND COULD BE CAUSING ACCELERATED WEAR - IRON APPEARS ELEVATED.
OTHER READINGS APPEAR TO BE NORMAL. RECOMMEND TO CHANGE OIL IF NOT DONE YET. INSPECT FOR SOURCE OF
DIRT ENTRY INTO THE SYSTEM. CHECK FOR UNUSUAL PERFORMANCE, HEAT, NOISES, VIBRATIONS, FLUID LEVELS.
RESAMPLE IN 125 HOURS TO MONITOR.

SO TO THE QUESTION:

Despite not wanting to pull apart the final drives with the wrong tools, not enough light, in a muddy forest - clearly these things need to be flushed out. How am I to do this? Cat suggests essentially multiple oil changes, possibly with a lighter oil, alternated with some mild operation. I see some suggesting pouring diesel in there, running it back a forth, drain and then a couple of fresh oil changes, resample after another 50 hours... ...the problem I assume is getting any kind or solvent out of there, if not creating more damage to seals or whatever else...

Whadya think?

Pictured are the sample capfuls, the water contaminated one is obviously lighter, and the manual snaps of the components. I can see pulling the outer covers, but if the oil sneaks around back of the center plate around the center gear and through the side rack/pin gear, then the muck is also much deeper in.

TIA - gibbs

 

[skyking1]

you're having too many kittens there with the oil analysis.
Let's review:
Oil sample says doom and gloom.
fix is not changing oil. Fix is total rebuild, new seals, and a blessing from the pope.
What do your feet on the pedals say? Do they work and track OK?

Listen to your feet.
For the kittens aspect, do a drain and change of oil. Do it more often than the schedule if that makes you happy, but do not go looking for trouble.
That is my two cents on a 17 year old machine with 4800 hours on it.

 

[Acoals]

Like Skyking said; relax, drain and fill, run for 50 hours, and drain again.

A side note, they spec something like a 50W final drive oil, not auto gear oil.

 

[Nige]

First & foremost............

 

[nonprod]

Like Skyking said; relax, drain and fill, run for 50 hours, and drain again.

A side note, they spec something like a 50W final drive oil, not auto gear oil.

Yeah, that seems to be a source of confusion too; Cat just sent me this OMM statement after reporting the heavy viscosity... (?!?)

I'm definitely up for the 'relax' - thanks!

 

[Nige]

You would have been far better with a TO-4 oil (doesn't have to be Cat) in the finals. SAE 50 would be the recommended viscosity.

Simply draining the oil is not going to get a lot of the contamination out, even if you got the oil stinking hot (which you can't) before draining it.

If you want to give the finals a good clean at some point then drain the oil, fill with the appropriate quantity of diesel, lift the track off the floor and run the travel mootr unloaded for maybe 5 minutes. Drain the oil. Repeat the process with the other side.

 

[nonprod]

I don't want to put too fine a point on it or question the years of experience represented here, but this CAT publication for the (Japanese) NAD 304CR, "SEBU7677-08" that they resent me really points in the other direction, for our temperatures out here, 14˚F - 122˚F, suggesting a pretty thick material, 85W-140...

...Just so I know what we're saying here: Despite what Cat says about, you guys would still recommend running a 50W To-4 in the final drives (I realize they still suggest using it elsewhere...)

thanks for the clarification - gibbs

 

[Old Growth]

SAE50 is about the same as 85w-140 gear lube.

Hydro Oil - Oil - Gear Lube all have different systems/numbers to rate viscosity.

I have found this chart handy.

 

[Nige]

Also because generally the excavator is not going to be moving far the final drives should generally not get that hot, therefore you would be closer to 85W on the gear oil scale which is actually lighter than 50 (note not 50W) on the crankcase oil scale which is the one used to classify TO-4 oil.

Cat generally specify TO-4 oils in all their final drives, no matter how large or small the machine is. This is the only occasion that I can recall coming across where they call for a gear oil. In the absence of information to the contrary I suspect that this particular product line was acquired as a result of a takeover and nobody bothered to change the original lubricant specs.

 

[Nige]

You shared the dealer lab’s interpretation of the final drive sample analysis results. Can you share the complete report.? I for one wouldn’t mind having a look at the numbers.

 

[nonprod]

thanks y'all, helpful information. Here's the actual reports:

 

[Nige]

The numbers for silicon are high and that IMO is what is triggering all the metals, except for the elements such as calcium, etc, which are additives in the oil. Molybdenum I'm also thinking is an oil additive, unless you added anything extra when you changed the oil previously.?

Both finals do need a really good cleanout - see my suggestions above with the addition that if at the first attempt the diesel/kerosene doesn't look clean when drained, rinse & repeat until it does. There is only 1 quart (approx) of oil in each final drive so it's not going to cost you much in fluid to clean it.

EDIT: I am also of the opinion that the "high viscosity" of almost 70 cSt in the results (according to the data sheet the oil viscosity is only 16.1 cSt @ 100°C) the lab saw could, at least in part, have been caused by the high amount of silicon present.

After that, despite the fact that the O&M recommends changing the final drive oil at 1000 hour intervals I would suggest to do it every time the engine oil is changed, again for the reasons above that the oil quantity in each one is so small. And I wouldn't recommend running the oil to 250 hours between changes either, at least until you have some good history with the machine.

 

[Nige]

After getting the internals of the final drives clean, your next challenege is keeping them that way.

In the diagram below the blue circled area just inboard of the drive sprocket flange (arrowed) is directly above the Duo Cone seal #8. This metal face seal is what is supposed to prevent contamination entering the final drive. The best plan is to keep that area as clean as possible so that dirt can't work its way into the gap between the fixed housing #3 and the rotating housing #9. The only thing you should NOT do is pressure wash it because that tends to drive the dirt inwards making things worse instead of better.

EDIT: In fact the lab interpretation confirms what I said above - CHECK FOR DIRT PACKING AROUND FINAL DRIVE AND INSPECT SEALS FOR ANY DAMAGE. CHANGE OIL AND FLUSH COMPARTMENT TO REMOVE CONTAMINANTS.

 

[Nige]

EDIT: I am also of the opinion that the "high viscosity" of almost 70 cSt in the results (according to the data sheet the oil viscosity is only 16.1 cSt @ 100°C) the lab saw could, at least in part, have been caused by the high amount of silicon present.

Or thinking more about it the elevated viscosity could be in part down to the molybdenum compounds, especially if someone prior to you added some moly grease to the finals at some point. Just another reason why they both need a good flush and not just an oil change.

 

[nonprod]

The numbers for silicon are high and that IMO is what is triggering all the metals, except for the elements such as calcium, etc, which are additives in the oil. Molybdenum I'm also thinking is an oil additive, unless you added anything extra when you changed the oil previously.?

Both finals do need a really good cleanout - see my suggestions above

EDIT: I am also of the opinion that the "high viscosity" of almost 70 cSt in the results (according to the data sheet the oil viscosity is only 16.1 cSt @ 100°C) the lab saw could, at least in part, have been caused by the high amount of silicon present.

do it every time the engine oil is changed

OK, yes, thank you for the detail. I did not add anything to the oil, but I bet Redline did. I see the logic in your cleanout technique, which seems intuitive to me also. I have not pressure-washed the area personally, though most of the machine's life was lived without me. It is the case that during my tenure, due to the nature of the lands where the machine lives, the tracks do accumulate a lot of muddy mess, and keeping it out of there may be a tall order, if one uses the machine to do any work. I'll have to figure out a way to get the cake off of there without at least a 25psi hose. But I take the point for sure; spraying mud into the mechanism is not helpful. I see the need in the drawing for some quality time spent examining the situation under there. I also think the notion that Final oil be changed 'abnormally' often is perfectly a fine preventative, and not expensive.

 

[Nige]

I also think the notion that Final oil be changed 'abnormally' often is perfectly a fine preventative,

Extremely muddy underfoot conditions would be classed as "severe" by the O&M Manual and of themsleves would predicate a shorter oil change interval on that particular component.

Most people don't realise that the fluid change intervals quoted in the manual are under ideal conditions until they read (or maybe don't read) the part that says "Products that operate in severe conditions may require more frequent maintenance."

 

[Tyler d4c]

Time for my comment that every one of these mini/ctl final drive threads get.

I don't care what the book says. (Unless it is more offen then this) says. Change the final drive oil same as engine oil or once a year. Most of these finals are 5 to 6 thousand dollars. 2 qt of oil is less then 50!

 

[nonprod]

Extremely muddy underfoot conditions would be classed as "severe" by the O&M Manual and of themsleves would predicate a shorter oil change interval on that particular component.

Most people don't realise that the fluid change intervals quoted in the manual are under ideal conditions until they read (or maybe don't read) the part that says "Products that operate in severe conditions may require more frequent maintenance."

Right, I see the logic here also. I hope I can find a way to get the muck off of there, which sometimes accumulates with every travel. We're in a remote place with endless fallen trees and other constant 'emergencies' and this machine is is our dog-send recourse device.

I may have neglected to mention that after the oil change I did 75 hours ago, the machine took a 3-mile journey through creeks and mud to get out to its home; and I'm not sure its previous owner did much of those kind treks. However, the guy I got it from, though he was coy about exactly what happened, (the natural buyer beware dynamics) apparently had one of his operators flip the thing into a bog somehow, bending up the cab, causing other issues, so who knows in what and for how long the tracks were submerged. At one point while looking for travel value hose leaks, I had to clear mats of mud and squirrel homes out of the nooks just under the swing rack gear, not so far from the operator feet position.

 

[Nige]

I hope I can find a way to get the muck off of there, which sometimes accumulates with every travel.

Even more reason to change the oil VERY frequently.

 

[BC Placer gold]

Make sure and ‘shovel’ tracks every night at quitting, important especially in winter/freezing weather. Also prevents flat-spotting on frozen carrier rollers etc. Hard to do perfectly, just do the best you can…I will clean tracks a few times on a long walk (10-12km). We have some bad clay in areas and it may take an hour to properly clean a 210 undercarriage for the lowbed…

The nature of our projects means long mob/demob distances in mountainous country from staging, so we are really diligent on final drive oil changes.

I flush with diesel while rotating tracks then TO-4 50. I often change oil based on distance and/or time. On long walks (swamping myself) I walk machine 1km then on foot to advance atv; allows time for cooling finals especially on long steep grades (they will get hot to touch). Last year 45km each on a 5 ton & 21 ton excavator….(not counting actual work on site)

I believe there is a thread on HEF where Nige has provided some really interesting data regarding the benefits of TO-4 oil in large mining equipment.

PS: we owned a Cat 304 & it was subject to the above noted arduous walking conditions. Frequent oil changes on finals, never any troubles…

Good luck!