Looking for lowest viscocity ATF

[bowlofsoup]

Does anyone know of an lube(oil/grease/atf) that has lower viscosity than 3800 cSt at -40c?
^ Primary question ^

For clarity, I am looking for ATF that remains most thin (low viscosity) at low temperatures My application for low viscosity automatic transmission fluid(ATF) is not a car transmission, but a small electric motor that has gears inside that will turn/spin very fast. If you are curious, https://www.youtube.com/watch?v=pH-52IgJui8 here is a video that might give you an idea of what kind of motor I am talking about. Many ATF that I've looked into have viscosities noted at, -40c, 40c and 100c. The inside of the motor isn't likely to get much warmer than ambient temperatures, so a very low viscosity ATF would be ideal. The lowest viscosity fluid I have found so far is http://www.mag1.com/ProductDetails.a...a-55f0b5c590fe this one, mag 1 low viscosity ATF. It's noted to be 28.56@40c(104f). Do you know of any ATF with lower viscosities? I am a little concerned about what viscosity these fluids will be at temperatures below freezing, I imagine it being like churning butter in the motor. Thanks!

[vgames33]

Is there any reason you are limiting yourself to an ATF? I'd think a standard motor oil would work fine in that gear set. 0w20 oils are the thinnest that I can think of.

[bowlofsoup]

Originally Posted by vgames33

Is there any reason you are limiting yourself to an ATF? I'd think a standard motor oil would work fine in that gear set. 0w20 oils are the thinnest that I can think of.

Thanks for the response. I've considered the idea of various types of oils, but I assumed there was some reason why something like an ATF fluid would be better for this application that other types of oils. I've been doing some searches and asking questions but I haven't found a definitive reason behind using one or the other. Surely there is a reason why one oil is classified as ATF and another is classified as motor. I just assumed that ATF fluid would be better as the application is somewhat similar and 'additives'. I did find redline C+ ATF that seemed to have a pretty good operating temperature range. I have done some searching around for viscosity ratings of 0w20 motor oil and haven't had any success in finding anything that beat the ratings I've found in 2 or 3 ATF. http://www.redlineoil.com/product.aspx?pid=53&pcid=9 (redline C+ atf) Vis @ 40°C, cSt 32.3 and Brookfield Vis @ -40°C, P 38 http://www.redlineoil.com/product.aspx?pid=137&pcid=9 (redline lightweight racing ATF) Vis @ 40°C 23.2 and Brookfield Vis @ -40°C, P 75 I think that what might be better to ask is, what oil keeps the lowest viscosity at lower temperatures?

[shorod]

Is the hub assembly you are working with sealed and designed to hold a fluid? Also, ATF has a bit of a solvent nature to it so you'd want to be sure the ATF will not attack or soften any of the internals, such as nylon gears and seals.

-Rod

[bowlofsoup]

Originally Posted by shorod

Is the hub assembly you are working with sealed and designed to hold a fluid? Also, ATF has a bit of a solvent nature to it so you'd want to be sure the ATF will not attack or soften any of the internals, such as nylon gears and seals.

-Rod

Thanks for the response, good question. No, the hub assembly was not designed to hold a fluid, but it was designed to resist the entry of water. Another individual who is doing something similar to this hasn't had any issues with leaking and hasn't used any sealant (to my surprise), but if leaking becomes an issue I plan to use 'ATF RTV sealant', which is a sealant designed to work with ATF fluid.

Personally, I am doubtful that ATF will have any kind of negative effect on plastics such as nylon. I think heat is something far more to be concerned with, but I certainly could be wrong.

http://www.professionalplastics.com/...ofPlastics.pdf Look at nylon 6 and greases/oils. Most of the types of plastics listed on this chart are labeled as good resistance to greases and oils.

[shorod]

I'm not sure how 3-in-1 oil reacts in low temperatures, but that could be another option for you here as that stuff is pretty thin, at least at room temp.

Is this motor going to be spinning at a faster rpm than what it was designed for or have a much higher duty cycle than designed for? If not, is there a reason you think you need a lubricant if the original unit was not intended to have one? I've been running R/C cars and trucks for years and many of them use nylon gears with no oil or grease. Some of mine are running 54,000 rpms with a brushless motor and LiPo batteries with no problems. The only times I've had issues with the gears melting is when the bearings fail and overheat. I've just recently switched to ceramic bearings to try to alleviate that issue which I've read from others has worked for them when having the same issue as me with a very similar setup.

So maybe adding a lubricant to the gear case is not the solution for your application. Maybe sourcing better bearings is where you should focus your search. Here is the site I used for ceramic bearings. Maybe they have something that will fit your application.

-Rod

[bowlofsoup]

Originally Posted by shorod

I'm not sure how 3-in-1 oil reacts in low temperatures, but that could be another option for you here as that stuff is pretty thin, at least at room temp.

Is this motor going to be spinning at a faster rpm than what it was designed for or have a much higher duty cycle than designed for? If not, is there a reason you think you need a lubricant if the original unit was not intended to have one? I've been running R/C cars and trucks for years and many of them use nylon gears with no oil or grease. Some of mine are running 54,000 rpms with a brushless motor and LiPo batteries with no problems. The only times I've had issues with the gears melting is when the bearings fail and overheat. I've just recently switched to ceramic bearings to try to alleviate that issue which I've read from others has worked for them when having the same issue as me with a very similar setup.

So maybe adding a lubricant to the gear case is not the solution for your application. Maybe sourcing better bearings is where you should focus your search. Here is the site I used for ceramic bearings. Maybe they have something that will fit your application.

-Rod

No need to try and convince me of the lunacy of this concept. I wrote quite a lot concerning your message originally, spent several hours pondering and researching, the conclusion I came to, putting it cripplingly short, is that I think your RC motor might benefit as much or more from this concept as my hub motor would. Aside from all that, I can assure you, the pros -heavily- outweigh the cons for my situation.

I'll give you a few short piece of information that might help sway you in your endeavors and assure you of the value of my own efforts.

This is the no load power consumption when the same motor is tested moments apart spinning at maximum RPM.

Dry: 76w
ATF: 44w

Next, imagine your bearings not caked in thick grease likely with some dirt mixed in that got trapped behind a seal, but the bearings open with clean, very low viscosity super lubricating ATF splashing on it and how that might effect their performance. If you wanted ceramic bearings, you probably really like the way this sounds, I know I do.

Back to the subject, if you can find me a product data sheet that describes a fluids viscosity that beats(lower is better) 3800 centistokes at negative 40c, I will probably be interested, this is what I am looking for.