Final Drive Oil Analysis

[Chrisso]

I feel like should be running 50wt TO-4.

Funnily enough Cat mysteriously changed their factory fill oil mid-production on the smaller 1.5 to 2T next-gen mini excavators from GO SYN 75W-140 to TDTO 30, approx 2021-ish. Yet to find any publication explaining why.

 

[Coaldust]

Funnily enough Cat mysteriously changed their factory fill oil mid-production on the smaller 1.5 to 2T next-gen mini excavators from GO SYN 75W-140 to TDTO 30, approx 2021-ish. Yet to find any publication explaining why.

The reason why, was the great c-19 force majeure.

Remember that thing that happened during that time period that shut down the refineries and the blenders? Remember Lubrizol burning down? Many of the index improver additives for synthetic blends were unavailable. Some still are unavailable in bulk form.

 

[Chrisso]

Remember that thing that happened during that time period that shut down the refineries and the blenders? Remember Lubrizol burning down? Many of the index improver additives for synthetic blends were unavailable. Some still are unavailable in bulk form.

That makes complete sense now you mention it. Lubrizol fire was Sept 2019.

Here I was thinking it was because the manufacturer realised TO-4 oils are more suitable for final drives.

 

[Dozerpusher]

Hi Guys, long time lurker, first time poster. I bought a certified used 2018 304e2 with 2000hrs from Cat about a year ago. This machine was Maintained by Cat from new, always on schedule and had oil analysis done at every service. So when I got it it had probably 8 samples done from each compartment between 2018-2023. Engine an Hydraulics look great. Final drives not so much. For the first 1200hrs or so they were changing the oil in the drives every 300-400hrs. And everything looked great. Then I guess theu decided to follow the manual and go 1000hrs on the oil without changing. It’s insane that this is Cats recommendation. They hold barely a half quart, roughly $8 worth of oil if you buy it from Cat. But I digress. Ever since that sample all subsequent samples have not been good. High iron, and chromium
, and high levels of oxidation.

My SOS advisor said the machine should be brought in to cat for inspection. It’s under warranty anyways. They pulled the covers off the finals and said everything looked great. Gears looked good. I assume there wasn’t any play suggesting bearing problems. They flushed out the drives to hopefully get out any residual metal from that long service interval. I pulled a sample 77hrs later when I was doing my yearly service and still iron was high, as was oxidation.

This whole time I been running Lucas 75w140, as that’s what cat sells you and the parts guy says it’s the only oil indicated for this machine. The service department uses the same oil. My SOS advisor thought that oil may be too thick for my climate. Not sure about that, I’m in Nc so it’s very hot. But she suggested I try 30wt TODO, which is TO-4 spec oil. So I flushed the drives again using Diesel and refilled with 30wt TODO. I’ve been doing some research since then and 30wt seems pretty thin. There isn’t really even a comparable SAE viscosity for the 140 gear I’ve been runnng. 90wt gear oil is like 50wt SAE. I guess 30wt is like 80wt gear oil. Seems like the recommendation is typically a 50wt TO-4 oil for final drives.

What do you guys think? I want to get the wear metals back to normal, if that’s possible. Or atleast get them wearing at a slower rate. I’ll probably pull a sample at 50hrs and see how things look. When cat had it in for inspection they pulled a sample on the oil that had been in there for just 16hrs and everything was elevated. So 50hrs should be plenty after the flush to get a good idea if this 30wt to-4 oil is doing a better job. I’ve attached the latest oil analysis on both drives. I appreciate any insight you guys can provide.

Get rid of that junk Lucas oil!!!! It’s some of the worst out there. If you want the best get Amsoil I’ve seen the difference first hand

 

[JfitzCat]

Jfitz,

The lab takes into account the oil you used. Especially, if the lube is Cat branded. They already have the spectro data in their system.

The fill amount in the O&M could be incorrect. That’s not uncommon.

High iron, early on, could be related to break-in. The 50ppm si marked as normal could have been a mistake by the lab tech who clicked the wrong pull down menu. Or, not. There might be enough data available in the system indicating these machines are trending higher than traditional si levels, for some reason, yet to be discovered. Poor contamination control procedures at the factory?

Pick a lube and stick with it, so we can actually start trending performance over time.

That’s already been done. Every sample over 6-7 years was the same oil, atleast if you trust what the dealer was recording on the sample cards (I think they were using something different earlier on based on the viscosity, but they were always writing the same oil type/weight). The trend was good samples for the first 3-4 years as they were changing the oil every 300-400hrs, then everything went bad when they 1000hrs without changing. Sample oil was used for the next 3 samples, all were bad. So now we’re trying new oils trying to see if we can reverse what appears to be a trend of excessive wear metals and try to get wear metals to return to normal or atleast lower.

 

[JfitzCat]

Get rid of that junk Lucas oil!!!! It’s some of the worst out there. If you want the best get Amsoil I’ve seen the difference first hand

Agreed, I have not been impressed with this Lucas gear oil at all. I’m thinking amsoil 80w90 severe duty would be a solid choice. Although I’m in a warm climate here in the south so there’s really no reason the recommended 75w140 would be too thick.

 

[JfitzCat]

FWIW so do I.

Nige, what’s your opinion on cat FDAO spec oil? I see you mostly recommend TO-4 in final drives but I don’t think I’ve seen you talk about FDAO. According to Cat this oil was developed specifically for final drives to address some shortcomings of TO-4 in planetary finals.

 

[Nige]

Nige, what’s your opinion on cat FDAO spec oil? I see you mostly recommend TO-4 in final drives but I don’t think I’ve seen you talk about FDAO.

There is a good reason for that. FDAO was developed specifically for mining machinery that runs 24/7 and is only very infrequently allowed to stop for long enough to go completely cold. Even if this was to happen there are electronic onboard protection systems that limit the machine travel speed until the differential/final drive oil is up to a certain minimum temperature. FDAO is also designed to be used in very heavily-loaded final drives. I'm talking 200+-ton haul trucks or D11-size dozers here

Your mini-ex neither operates 24/7 nor has protection systems for cold oil. Neither does it travel sufficient distance to get the oil hot and keep it hot. Therefore my opinion would be to not recommend FDAO oil which is an SAE60 viscosity. It also goes some way to explaining why the final drive oil recommendation is a 75W/140 GO.

 

[JfitzCat]

There is a good reason for that. FDAO was developed specifically for mining machinery that runs 24/7 and is only very infrequently allowed to stop for long enough to go completely cold. Even if this was to happen there are electronic onboard protection systems that limit the machine travel speed until the differential/final drive oil is up to a certain minimum temperature. FDAO is also designed to be used in very heavily-loaded final drives. I'm talking 200+-ton haul trucks or D11-size dozers here

Your mini-ex neither operates 24/7 nor has protection systems for cold oil. Neither does it travel sufficient distance to get the oil hot and keep it hot. Therefore my opinion would be to not recommend FDAO oil which is an SAE60 viscosity. It also goes some way to explaining why the final drive oil recommendation is a 75W/140 GO.

Good info. So a say 315-325 size machine or smaller dozers still call for TO-4 in the final drives? FD-1 oil is only recommended in big mining machines that are running basically around the clock, never really letting the oil get cold, or with computer controlled warm up procedures. it’s not that they’ve switched all non compact equipment over to FDAO, only very specific equipment.

Regarding your comment on why they spec 75w140 in my mini x. Based on what you’re saying something like 50wt TO-4 wouldn’t even be a good option since it’s too thick when cold, and may not even warm up sufficiently for that 50wt oil to flow well? So I’d be better off sticking with this 30wt todo, or a multi viscosity gear oil.

 

[Nige]

So a say 315-325 size machine or smaller dozers still call for TO-4 in the final drives?

Correct. Actually in the excavator range everything from a 308E-upwards calls for TO-4. This is why people like me who have only worked with larger equipment using TO-4 (and its predecessor TO-2) find it difficult to believe that GO oils are specified for Cat final drives on ANYTHING.

FD-1 oil is only recommended in big mining machines that are running basically around the clock, never really letting the oil get cold, or with computer controlled warm up procedures. it’s not that they’ve switched all non compact equipment over to FDAO, only very specific equipment.

Again correct.

Regarding your comment on why they spec 75w140 in my mini x. Based on what you’re saying something like 50wt TO-4 wouldn’t even be a good option since it’s too thick when cold, and may not even warm up sufficiently for that 50wt oil to flow well? So I’d be better off sticking with this 30wt todo, or a multi viscosity gear oil.

All I can say is that on a slightly larger excavator (308E) both TO-4 SAE30 & SAE50 are listed as options.
SAE30 is for an ambient temperature range of -20 to +25 C
SAE50 is for an ambient temperature range of -10 to +40 C

As a comment if you were using SAE30 and the temperature went a bit above above 25C that wouldn't mean you would have to stop work.....

IMHO with your location a TO-4 of either 30 or 50 would work.

 

[Coaldust]

From a Chevron perspective, FDAO isn’t formulated with the friction modifier additive package required for clutches and brakes. That’s the major difference between TO-4 and FDAO.
Next, is probably the cost. FDAO is expensive.

 

[Coaldust]

From a Chevron perspective, FDAO isn’t formulated with the friction modifier additive package required for clutches and brakes. That’s the major difference between TO-4 and FDAO.
Next, is probably the cost. FDAO is expensive.

 

[Nige]

From a Chevron perspective, FDAO isn’t formulated with the friction modifier additive package required for clutches and brakes. That’s the major difference between TO-4 and FDAO.

Good point. FDAO is only designed for use in rear ends.

 

[JfitzCat]

Correct. Actually in the excavator range everything from a 308E-upwards calls for TO-4. This is why people like me who have only worked with larger equipment using TO-4 (and its predecessor TO-2) find it difficult to believe that GO oils are specified for Cat final drives on ANYTHING.

Again correct.

All I can say is that on a slightly larger excavator (308E) both TO-4 SAE30 & SAE50 are listed as options.
SAE30 is for an ambient temperature range of -20 to +25 C
SAE50 is for an ambient temperature range of -10 to +40 C

As a comment if you were using SAE30 and the temperature went a bit above above 25C that wouldn't mean you would have to stop work.....

IMHO with your location a TO-4 of either 30 or 50 would work.

Here in Nc it’s over 25c (77f) for half the year. With a good 3-4 months well over 80 and into the 90s and even 100. We’re getting into this time of the year now. But I’ll probably run this 30wt to-4 for a while and pull a sample before considering a switch to 50wt. I’d have to See what my sos advisor says too since the machine is under warranty.

 

[Nige]

Let me put the question a different way. What is the MINIMUM ambient temperature at your location.?

 

[Angry Mike]

Actually for the OP's particular S/No it's recommended to change every 1000 hours, but IMO anyone who doesn't change the final drive oil every time they change the engine oil needs their head read.........

This type of machine can end up walking miles, and for 1 litre of oil per side it's worth it just for peace of mind. YMMV.

View attachment 308469

Ah i stand corrected, my dealer has us do it at every 500 so i assumed that was a CAT standard

 

[JfitzCat]

Ah i stand corrected, my dealer has us do it at every 500 so i assumed that was a CAT standard

cat just wants to make the cost of ownership look as low as possible, hence the long intervals in the manual. Most dealers want to ensure the greatest longevity for your machine. Mine recommends 500 for the minis as well. And 250 for skid loaders since they typically spend alot more time tracking around. I do my mini at 250 as well. It’s too cheap and quick not to.

Also, I think with minis cats really only focused on the first 3000hrs of ownership. I don’t think you’d have much trouble getting to 3000hrs with 1000hr OCIs for the finals.but idk how far past that you’d get with 1000hr ocis. You probably be replacing final drives not far past 3000 with only 3 oil changes in the past 3000hrs..

 

[JfitzCat]

Let me put the question a different way. What is the MINIMUM ambient temperature at your location.?

Between Nov-March Typically about 35-40 degrees F is the coldest it’ll be when I run the machine. With the very very occasional sub 20 degrees temp. I’m good about doing a thorough warm up though. Usually limit it to slow speed for a while before kicking into 2 speed.

 

[Nige]

Between Nov-March Typically about 35-40 degrees F is the coldest it’ll be when I run the machine. With the very very occasional sub 20 degrees temp.

OK so 20F is -6.5C. -10C is 14F.
As posted above -

SAE50 is for an ambient temperature range of -10 to +40 C

With 40C equalling 104F......
I stand behind my earlier recommendation of SAE50 TO-4.

 

[nonprod]

Thanks all for ongoing discussion on this, albeit to some extent redundant. I'm wrestling with similar issues described some here: https://www.heavyequipmentforums.com/threads/304cr-final-drive-alarmist-oil-sampling.106987/

...especially the cleaning out of mud and crud from the seal area Nige graciously posted in the above thread,; I can say I was on my back just yesterday with a sort of custom scraper tool I made, digging crap out of the cavities on the 304 with nearly 5000hrs, without removing the track. It may not be any less futile than a lot of other sorts of remote property management I'm involved with year round! At this point, I'm not a big fan of the design, to make a critical seal area so prone to mud cakes so inaccessible, but I'm not a mechanical engineer. I'm just a schlub who's seen too many pictures of WWI tanks, thinking they managed to work in the trenches, at least for a minute or two.

I've done a bunch of flushing and oil changes also, and taken y'all's advise to run TO-4 50 - holding my breath on another set of SOS in 100 hours or so. I do a significant amount of travel and dozer work with the thing. Anyway, I have a tendency to over-think things and it is helpful when all the experience here says relax, change the oil often, it's cheap, and pay attention to how the machine responds.

Please report back with your ongoing experience on the matter.

-gibbs