Gear Oil Help

I need some recommendations for a 85/140 synthetic oil....or a better substitute

I think the problem is incredibly high heat in this application.
The application is a hyd powered gear head on a mulcher.

Does the manual for the equipment call for that viscosity of oil..? The reason I'm asking is that maybe the oil itself is causing the heating due to a "churning" effect. This might be due to either viscosity, oil level too high or a combination of both. What moving parts exactly are inside the gear head, just bearings and gears..? Options available would be an either an 80W/90 gear oil if you want to go lighter and stay with EP oil, an SAE60 FD-1 oil or maybe even an SAE50 grade TO-4.

What NIGE said. What does the manual call for?...and go from there. Lighter is generally better for heat dissipation.

85/140 synthetic is what the manufacturer recommended..... but no other specs as far as I know.

BTW, this isn't my machine but belongs to a company I work pretty close with. I hope that explains the delay in my response and my lack of knowledge in some areas

Nige, thanks for jumping in. The gearbox is just gears and bearings and overfilling is something that I will look into as it is a real possibility. Almost every gearbox around here is overfilled.....but they are only used forty hours a year or so. This could be a case of what we do at home.....we don't do here

I have been pushing for oil service on these machines to see where we are at maintenance wise. Right now there is a component out and we don't know anything as to why. It's not my money...but it's not proactive managment and I don't like that Oil service is looking a lot better to see at what point this oil is breaking down

There is a matched set of these machines so we can run comparable samples of different oils at the same time.....on the same job with under the same conditions.

Any thoughts???

http://www.belray.com/sites/default/files/pds_files/Synthetic Gear Oil_11.pdf

If you have been having high heat I would use the ISO 220. Technically the ISO 320 = SAE 85/140 but the lighter oil will carry heat away better. The Belray gear oil has high EP (100 lb timken), its

Like Nige said make sure its not overfilled. If its vented I would recommend adding a quality desiccant breather to keep it clean and water free.

Keep clear of gear oils that have moly or other solids. After time the solids tend to congeal and gather together shortening the life of the oil.

Actually, Moly is a FANTASTIC proven friction modifier and will only serve to help reduce heat.
"There is a matched set of these machines so we can run comparable samples of different oils at the same time.....on the same job with under the same conditions.

Any thoughts??? "
An excellent idea

I personally wouldn't run any lubricant with an MoS2 additive in a gearbox of any type where the bearings were running at "high speed". Moly tends toencourage the rollers or balls on the rolling element bearings to skid rather than roll.

roddyo,
Purge the gear boxes, replace with a good high quality oil that meets the SAE 140 spec or ISo 320( which is still on the lighter side of the spec) make sure your fill level is correct.

salesrep said:

http://www.tandfonline.com/doi/abs/10.1080/10402008808981830?journalCode=utrb20#preview

Click to expand...

Id like to read the whole article but Im not paying $100.00 to read it.

I agree MoS2 is a great solid additive in a solid or semisolid, grease, ogl, dry film.... but

MoS2 in my opinion doesn't belong in gear oil. Putting any solid in a liquid is risky in my opinion. Ive seen too many suspended solids in gear oils start to cling to each other. They cling together and fall out of suspension and plate out where they shouldn't, basically same thing Nige said. Also if you ever try use a fine filtration system you run the risk of taking the moly out. Now if we're talking soluble molys ( Molybdenum di-2-ethylhexyl phosphorylates) that may be a different story.

salesrep said:

Actually, Moly is a FANTASTIC proven friction modifier and will only serve to help reduce heat.
"There is a matched set of these machines so we can run comparable samples of different oils at the same time.....on the same job with under the same conditions.

Any thoughts??? "
An excellent idea

Click to expand...

HaHa how much gear oil does each one take? Maybe you can get your oil for free, Salesrep can sample some Shaeffers and Ill sample some Belray.

I have had good luck with Amsoil in problimatic gear boxes. Talk with a local rep or pm me for the name of my local rep they are knoledgable on the specs and all aspects of oil as Amsoil offores a wide varity of clases to them. Even if you don't end up going with Amsoil they can help you understand what could be causing this and interprit the oil sample readings.

Moly used in the proper forms will not come out of suspension or be filtered out in gear oil or engine oil. This is a proven fact going back many decades. A simple google should suffice anyones curiosity on Moly.
Amsoil makes some good syn gear oils...go for it, I am sure belray does too.

That sounds like a plan blitz They hold less than a 5 gallon bucket each...wink, wink

It would make for some interesting oil samples, gear box temps etc.

I'm guessing Nige would say go with 80/90 weight??? We may need another mulcher.lol

As much as oil recommendations, I'm interested in everyone's thoughts as to oil sampling protocols to catch this problem in the future. Or basically.... where would YOU go from here with this problem?

I'm not really prepared to stick my neck out and suggest anything specific without having seen the device in question, or at least a sectioned parts drawing of it. If there are 2 machines and one's giving the problem and the other one isn't (that's what seems to be implied) then I'd be looking to find out "what's right" on one and "what's wrong" on the other.

you say there is "A component out". You mean one of the gear heads, right..? What failed..? Can you post some photos of broken iron or was it a case of go in there with a shovel and dig all the broken bits out..?

My plan would be something like: -

1. Make sure oil levels are correct and not over-filled.
2. Change oil using the recommended 85W/140 synthetic oil in both and see if getting oil levels spot-on correct has changed anything. Make sure oil is hot when drained and if necessary fluch the case with a bit of fresh oil until it's clean inside.
3. If the answer to 2 is "no", what exactly is happening..? Excessive temperature, oil foaming..? Need an infra-red temp gun to shoot the case temp while working. The temp gun is NOT an option, it's essential.
4. Now the time comes to start experimenting, but only in 1 machine - keep the other one standard to use as a baseline. If the recommendation was synthetic try switching to mineral oil, if it was mineral try synthetic. Any difference..?
5. If no try a lower viscosity oil like 80W/90 (again try both synthetic and mineral).

You mentioned earlier that these machines only work about 40 hours/year. That's about 1 hour/week, or do they work for longer periods (say 10-20 hours continuous) and then sit for 6 months before they work again..?

Somewhere along the line you'll find what works, but you have to trial different things in a structured way that enables you to measure your results and compare them to your baseline.