LX2980 question re: reduction box oil foam

[AJS]

I have the 64 in LX2980 on my LX3310, very happy with it. I recently unscrewed the bolt on the side of the reduction case to check the gear oil level after running the blower briefly. As I loosened the screw, out came---foam! The foam disappears after a while when not using the blower. I was concerned about water or contaminants in the oil so I drained the reduction case, flushed it with new gear oil, and refilled it to the side plug level per instructions. Ran the blower for a few minutes, loosened the level check bolt, and foam again. At this point I'm pretty sure there are no contaminants present, and no water other than what's present in the air in the box with our humid Pacific NW climate. Since the reduction box is only partially filled with gear oil, I'm wondering if perhaps the foaming after use is inevitable and due to mixing with the air. Have any of you with a LX2980 checked the reduction box oil at the level port after running your blower? I welcome comments, thanks.

(I’m hoping someone with a LX2980 is willing to check their reduction oil after running the blower for a few minutes so I can know whether the foam happens with this model, or do I have a problem with my setup)

 

[animals45]

Have ya had it since new ? Could it be that someone put detergent oil in the gear box ?
animals45

 

[AJS]

Have ya had it since new ? Could it be that someone put detergent oil in the gear box ?
animals45

Yes, bought it new, prepped by dealer. No way to be absolutely sure that never happened but I would hope that draining and flushing with new oil would take care of that. Thanks for the idea.

 

[DustyRusty]

If you want to flush the reduction box, I would flush it with diesel fuel to get all the old gear oil dissolved. Then I would add fresh gear oil and run it for a few minutes, drain that gear oil, and refill a second time with fresh gear oil. Gear oil shouldn't foam, and if it is, then I would be inclined to believe that there is something wrong with the gear oil that you are using. Another thing to check is if there is any brass in the reduction box and if there is, I would only use GL4 in it. GL5 is known to attack yellow metals.

 

[AJS]

If you want to flush the reduction box, I would flush it with diesel fuel to get all the old gear oil dissolved. Then I would add fresh gear oil and run it for a few minutes, drain that gear oil, and refill a second time with fresh gear oil. Gear oil shouldn't foam, and if it is, then I would be inclined to believe that there is something wrong with the gear oil that you are using. Another thing to check is if there is any brass in the reduction box and if there is, I would only use GL4 in it. GL5 is known to attack yellow metals.

Thanks for your reply. I will do the flush procedure you describe, more thorough than what I did. Yes, I'm thinking now that I'm not using the right oil. I got SAE80-90 off the local shelf. Kubota specifies SAE80-90 AGMA 5EP - synthetic extreme pressure with additives. I'll use the AGMA 5EP, found a couple sources. No brass that I can find. Many oils do not give the copper corrosion rating with specs. Thanks again, I'll post if it works.

 

[DustyRusty]

Thanks for your reply. I will do the flush procedure you describe, more thorough than what I did. Yes, I'm thinking now that I'm not using the right oil. I got SAE80-90 off the local shelf. Kubota specifies SAE80-90 AGMA 5EP - synthetic extreme pressure with additives. I'll use the AGMA 5EP, found a couple sources. No brass that I can find. Many oils do not give the copper corrosion rating with specs. Thanks again, I'll post if it works.

Please post either way. That way we all learn from other's experiences. I usually drain mine during the hot months of summer, however, this summer I just forgot to do it. It is on my short list of things to do during a warm day. The problem is that I have way too many projects and not enough time left to complete them all.

 

[TheOldHokie]

Thanks for your reply. I will do the flush procedure you describe, more thorough than what I did. Yes, I'm thinking now that I'm not using the right oil. I got SAE80-90 off the local shelf. Kubota specifies SAE80-90 AGMA 5EP - synthetic extreme pressure with additives. I'll use the AGMA 5EP, found a couple sources. No brass that I can find. Many oils do not give the copper corrosion rating with specs. Thanks again, I'll post if it works.

Kubota continues to use antiquated specifications. Monograde SAE 80 and SAE 90 gear oils are a thing of the past.

AGMA is just another oil viscosity rating system. It is industrial as opposed to automotive oriented and like the ISO system the viscosity grades are defined at 40C. The AGMA 3 specification is 90 to 110 cSt @ 40C.

The SEP suffix means:

S = Synthetic
EP = Extreme Pressure additive

A modern SAE 75W90 GL5 synthetic gear oil matches all of those specifications. The vast majority test 1C or lower on the D130 copper corrrosion test. Many are 1A or 1B and they all pass multiple anti-foaming tests.

I think your concerns are probably missplaced and what you are seeing is just the nature of the beast.

Dan

 

[AJS]

Please post either way. That way we all learn from other's experiences. I usually drain mine during the hot months of summer, however, this summer I just forgot to do it. It is on my short list of things to do during a warm day. The problem is that I have way too many projects and not enough time left to complete them all.

Will do. I have a lot of "learning experiences".

 

[AJS]

Kubota continues to use antiquated specifications. Monograde SAE 80 and SAE 90 gear oils are a thing of the past.

AGMA is just another oil viscosity rating system. It is industrial as opposed to automotive oriented and like the ISO system the viscosity grades are defined at 40C. The AGMA 3 specification is 90 to 110 cSt @ 40C.

The SEP suffix means:

S = Synthetic
EP = Extreme Pressure additive

A modern SAE 75W90 GL5 synthetic gear oil matches all of those specifications. The vast majority test 1C or lower on the D130 copper corrrosion test. Many are 1A or 1B and they all pass multiple anti-foaming tests.

I think your concerns are probably missplaced and what you are seeing is just the nature of the beast.

Dan

Thanks Dan. I appreciate your oil rating discussion. Before this issue my feeble knowledge of oil ratings was limited to SAE viscosities. I find the widely available viscosity chart showing comparison of the different ratings to be helpful. https://www.thelubricantstore.com/understanding-the-viscosity-grade-chart

My sometimes-obsessive head is not quite ready to accept the foaming as normal. It's easy enough to do the thorough flush and use oil that definitely matches Kubota's stated specs (synthetic, extended protection, additives) which is not the case for the oil I did use, my error. At least then I'll know that I did everything I could and hopefully minimize the 2AM "shoulda done that" awakenings. I see Kubota markets their branded gear oil though specs are sparse. Amsoil makes a synthetic EP SAE 80-90 with additives that looks like it fits. https://amsoilcontent.com/ams/lit/databulletins/g2043.pdf And as you point out there are others. Thanks again for sharing your knowledge.

 

[TheOldHokie]

Thanks Dan. I appreciate your oil rating discussion. Before this issue my feeble knowledge of oil ratings was limited to SAE viscosities. I find the widely available viscosity chart showing comparison of the different ratings to be helpful. https://www.thelubricantstore.com/understanding-the-viscosity-grade-chart

My sometimes-obsessive head is not quite ready to accept the foaming as normal. It's easy enough to do the thorough flush and use oil that definitely matches Kubota's stated specs (synthetic, extended protection, additives) which is not the case for the oil I did use, my error. At least then I'll know that I did everything I could and hopefully minimize the 2AM "shoulda done that" awakenings. I see Kubota markets their branded gear oil though specs are sparse. Amsoil makes a synthetic EP SAE 80-90 with additives that looks like it fits. https://amsoilcontent.com/ams/lit/databulletins/g2043.pdf And as you point out there are others. Thanks again for sharing your knowledge.

I like the Amsoil 75W90 better. After all its a snowblower. Any of the synthetic gear oils are going to work.

EP = extreme pressure as tested by measuring wear using a hypoid spiral bevel drive axle.


All gear oil gets air bubbles in it. The issue is do they burst or persist and accumulate. The ASTM foaming tests simply measure how quickly they break up once the agitation stops. Generally that means pretty much all gone after a 10 minute settling time. If its got an API srrvice rating it passes all three foaming tests.

Dan

 

[AJS]

I like the Amsoil 75W90 better. After all its a snowblower. Any of the synthetic gear oils are going to work.

EP = extreme pressure as tested by measuring wear using a hypoid spiral bevel drive axle.


All gear oil gets air bubbles in it. The issue is do they burst or persist and accumulate. The ASTM foaming tests simply measure how quickly they break up once the agitation stops. Generally that means pretty much all gone after a 10 minute settling time. If its got an API srrvice rating it passes all three foaming tests.

Dan

More helpful information, thanks.

 

[Snowman7]

I will be checking my fluids soon and try to remember to get back to you.

 

[MapleLeafFarmer]

If you want to flush the reduction box, I would flush it with diesel fuel to get all the old gear oil dissolved. Then I would add fresh gear oil and run it for a few minutes, drain that gear oil, and refill a second time with fresh gear oil. Gear oil shouldn't foam, and if it is, then I would be inclined to believe that there is something wrong with the gear oil that you are using. Another thing to check is if there is any brass in the reduction box and if there is, I would only use GL4 in it. GL5 is known to attack yellow metals.

I too like the idea of a diesel or two flush when water is present.
We do it all the time to atv's/SxS etc.... that drowned out crossing swamps, etc... Probably 1/2 dozen a year or so that way.
In severe water cases we make 3 flushes and even in most severe cases cleans it out.
Don't need to operate gearbox very long each flush and a diesel flush is material cheap.

 

[AJS]

I will be checking my fluids soon and try to remember to get back to you.

Thanks, look forward to hearing your experience. I only ran the blower for a couple minutes before finding the foam.

 

[AJS]

Follow-up for anyone following this thread. I did the diesel flush x 2, filled the reduction box with new oil (the Amsoil synthetic EP, per reccs above and Kubota specs), ran the blower briefly, drained the oil and refilled with new oil to the fill hole. Ran the blower and foaming looks the same as before. Foam comes out the level check port as I loosen the bolt, and continues to boil out if I take out the bolt, indicating it is more than just surface foam.

I feel I have done all I can do - thorough flush, using the right oil. My reading indicates that anti-foaming additives bring their own problems so I'm not inclined to go there. So I guess I accept it as "nature of the beast" as Dan suggested. I'm not a heavy blower user, just my long driveway, so hopefully any reduced lubrication effect will be tolerated.

Thanks to those who generously shared their knowledge here and welcome any further thoughts.