Reduction Gear Oil Change - Benefits for Range

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knightmb

Well-known member
Joined
Jan 12, 2015
Messages
2,212
Location
Franklin, TN
Rather than keep hijacking this topic https://mynissanleaf.com/viewtopic.php?f=38&t=25076 I am starting a new one to focus on the benefits that I have noticed with my Reduction Gear Oil change (both my 2013 and 2020 Leaf). All of this is anecdotal evidence because I don't exactly have a lab or team of interns to help me record large amounts of data :D

But... I do have a lot of "trips" that I drive that are the same distance, same time of day, as part of my job. So it's real easy to let Nissan do the heavy lifting for data collection and just compare before and after oil changes efficiency for the trips.

For example, I have a route from Merchant A to Customer B that is always the same distance, same time of day. So before and after my gear oil change, I can notice a difference in efficiency that the vehicle itself is recording. What is special about this route? It has no stop signs, no stop lights, very little traffic, speed limit is 70 MPH. It's very easy to start the route, turn on cruise control, reach the end and I know the vehicle did a consistent speed all the way regardless of how steep the hill climb was or how far down the other side of a hill it does regen to maintain the speed. The numbers from the Nissan website reflect that, up until the gear oil change it was easy to predict what miles / kWh I would get on that trip. So anything more or less means something has made a difference. It could be the weather, maybe I got stuck behind someone slow and was drafting the whole way, I wasn't running the heat or AC, etc. Luckily, this month of April has made it not necessary to run heat nor AC, so it helps to keep these data points pretty consistent to follow.

25.1 miles 3.6 miles/kWh
25.1 miles 3.6 miles/kWh
25.1 miles 3.6 miles/kWh
25.1 miles 3.6 miles/kWh
25.1 miles 3.9 miles/kWh <- Gear Oil Change

So while I could post up pages and pages of data like this, you can read some of that in the other topic, I would rather get to my conclusion of what I am seeing rather than giving up endless pages of copy/paste data from the Nissan website.

For reference, I used this in my Reduction Gear Oil Change: https://www.valvoline.com/our-products/automatic-transmission-products/ulv

When driving +70 MPH, it seems my trips are 0.3 miles/kWh better. I don't have many that take me on the interstate for high speed driving, so that is about the best I could see with the data I have.
When it comes to trips that are 55 MPH and under, I see an average benefit of 0.5 miles/kWh better. I have a lot of those to compare before and after the gear oil change.

The GOM in any Nissan Leaf is famous for being very optimistic about range when fully charged, we even joke about it a lot, but it does give one a way to see if the vehicle itself thinks it is getting better or worse range. When I first bought my Leaf, the GOM would show about the 220 miles range, which I was fine with since I knew the EPA rating for it was 215 miles at best. I knew it would be guessing high, I came from a 2013 Leaf and expected as much. Ever since my Reduction Gear Oil change though, the GOM has been going higher and higher for the last couple of weeks. I know I'm not somehow driving better or that I am getting magic tail winds at every trip, so something was helping the Leaf range and the even itself knew it. Finally today, the highest GOM range I've ever seen. My weekly driving average is usually about 3.9 miles/kWh and has been that way for a long time. It appears now that my weekly average has been boosted to 4.4 miles/kWh, which was surprising since I have been using the AC on a few hot days.

I know I said it in the other topic, I wasn't going to give the ULV fluid much credit, but now it is hard to deny that it is making a fairly descent gain on range for me and my driving style. How do those numbers translate into actual range you might ask?

If @ 70 MPH, my old efficiency driving was 3.6 and the ULV gear oil bumps that up to 3.9, that is an extra 17 miles of range at high speed if I want to drive the EV from 100% to 0% SOC. Not amazing, but if you are trying to reach a charge station at good speed with good climate control going and just not worrying about it, that 17 extra miles could be a good confidence booster.

My under 55 MPH trips, that 0.5 boost nets me +28 extra miles (100% to 0% SOC). The slower my average drive speed, the more miles I gain from the efficiency boost and that is probably why my GOM is guessing so dang high!

uhjsWUJ.jpg
 
Good idea starting a new thread. The other one was as worn out as a Gearbox at 200,000 miles.

It does look like your results are undeniable. Which means you're indeed operating nearer the lowest point on the Stribeck Curve than what Nissan Matic S would give you. Like I said in the other thread, maybe single-digits % more wear rates, up to 10% or so. Not a big deal, especially if you get out the metal shavings on the magnets every 70k miles or so.

Nissan, for future Leaf production, and Ariya coming soon, should get a nice bump up in range by specifying the newest generation of "ultra low viscosity" (ULV) ATF oil like the Valvoline ULV you're using.

I'm planning on sneaking into the plant in Smyrna, & substituing out their vats of Matic S ATF with the Valvoline ULV goop, like in Mission Impossible where Cruise had to lower himself into a room thru the roof. ... If you DON"T read about this in the news later, you'll know I succeeded without being detected. .... Yer welcome, Nissan. ("Yer mission, if ya decide to accept it, ...")

Seriously though, I do need to contact somebody either at NREL, INL, or ORNL (all those Federal Laboratories spending our tax dollars on figuring out EVs) to ask them the obvious question "Why not get an easy instant boost in range by using Valvoline ULV? What's the hold-up here?"
 
voltamps said:
"Why not get an easy instant boost in range by using Valvoline ULV? What's the hold-up here?"

Could it be an improvement they are holding onto for use with future models? I'm sure Nissan aren't implementing every improvement as quickly as they can. EVs are a competitive and growing market, and Nissan is clearly in this long haul.

I'd have a running list of ideas and would be pulling from it only as needed. I'd want some easy to implement improvements in my back pocket for the years that larger improvements fall flat.

It's one thing to maximize the efficiency of an EV, it's another to keep a car model alive year after year.
 
voltamps said:
Nissan, for future Leaf production, and Ariya coming soon, should get a nice bump up in range by specifying the newest generation of "ultra low viscosity" (ULV) ATF oil like the Valvoline ULV you're using.
....
Seriously though, I do need to contact somebody either at NREL, INL, or ORNL (all those Federal Laboratories spending our tax dollars on figuring out EVs) to ask them the obvious question "Why not get an easy instant boost in range by using Valvoline ULV? What's the hold-up here?"
I wonder if it would take a lot of "engineering" to design future EV gear boxes to just work with the ULV from the factory? Seems that as battery sizes get bigger, that small bump in efficiency adds up to more and more miles.

So, in a perfect battery world, say the Gen 1 Leaf with the 24 kWh, would only get (perfect battery math 24 x 0.5) 12 extra miles of range, but those with larger battery packs 40, 62 kWh, would gain additional 40 x 0.5 = 20 miles, 62 x 0.5 = 31 miles. A future battery pack that was 100 kWh would gain an extra 100 * 0.5 = 50 miles.

The gains are small with a smaller battery pack, but increase proportionally as the battery size gets bigger. I didn't design the Nissan Leaf and the original engineers probably didn't worry about gear box fluid visocity because of the small gains on the smaller battery. Nissan would probably need to be able to produce or buy it's own *official* ULV fluid and maybe that just wasn't a big priority at the time since they already had the Matic S ATF that was good enough. The ULV may have required extra years of testing to make sure the gears can hold out and they don't want to fall behind the other car companies, who knows?
 
knightmb said:
Nissan would probably need to be able to produce or buy it's own *official* ULV fluid and maybe that just wasn't a big priority at the time since they already had the Matic S ATF that was good enough. The ULV may have required extra years of testing to make sure the gears can hold out ...

I'm sure that's it right there. One ATF to rule them all; one less variable for R&D testing, production, dealers... and the volume of LEAF production probably doesn't warrant upsetting that cart.
 
G3NG4R said:
voltamps said:
"Why not get an easy instant boost in range by using Valvoline ULV? What's the hold-up here?"
Could it be an improvement they are holding onto for use with future models?

Bottom Line: 8% EPA Range Boost is Gold in the market. Reduces carbon footprint fleetwide (powerplant emissions) too. That would boost a 40 kWH Leaf like mine to 162 miles (from 150). A 226 mile S Plus model would get 249. That sells more Leafs.

Looks like, not sure, but it looks like @knightmb is getting 8% better range using thinner ATF fluid. @estomax is going to try it soon too. I just spent a wad on Amsoil SS PAO ATF & still need to know my wear rates are way down before I use it. Tempting.

(( Note to most readers: Nissan Matic S is the official fluid to use. It's good stuff of course. Nissan says never change it; I say every 60k miles. ))

knightmb said:
The ULV may have required extra years of testing to make sure the gears can hold out ...
I get the arguments that Nissan didn't want to stock or spec a new ATF fluid, and the ULV low-visc oil would need testing. Still, the range bump is just too nice.

Thin ULV ATFs have been on the shelves for 4 years now as a commodity. Slap a Nissan OE label on a Mercon ULV bottle & it's done.

It's easy to measure gearbox wear rates at big company's labs.

Lubrizol, Afton, Infineum, Oronite, etc., all the ATF fluid companies who work with big blenders, can test the wear rate (mass steel shed per mile) in that simple fixed gearset in about a month, taking it to several thousand miles, weighing-measuring, & taking a gander at the Ra RMS roughness, looking for pitting, etc. of the gear teeth & bearings. Easy test.

In addition, they can formulate a standard anti-wear ATF additive package (Dexron VI type chemicals) tweaked with esters & more phosphors to help the low-visc base oil, and remove most of the VII plastic polymers to avoid long-term mechanical shearing which reduces visc too much over time. Actually all that describes "ULV" ATF which came out 4 years ago. It might even be made to naturally oxidize slightly to keep the visc up stretching out to 50k+ miles in a tranny or gearset.
 
voltamps said:
In addition, they can formulate a standard anti-wear ATF additive package (Dexron VI type chemicals) tweaked with esters & more phosphors to help the low-visc base oil, and remove most of the VII plastic polymers to avoid long-term mechanical shearing which reduces visc too much over time. Actually all that describes "ULV" ATF which came out 4 years ago. It might even be made to naturally oxidize slightly to keep the visc up stretching out to 50k+ miles in a tranny or gearset.

Another excellent point I didn't think about, if ULV ATF is new, then nearly all the EV manufactures wouldn't be designing anything to use it anyway, certainly not in the late 2000s when Tesla, Nissan, and the likes were pushing out BEV. They used what was best known at the time, ICE relative ATF fluid with the lowest, safe viscosity. Thanks for pointing that out!
 
voltamps said:
Looks like, not sure, but it looks like @knightmb is getting 8% better range using thinner ATF fluid. @estomax is going to try it soon too. I just spent a wad on Amsoil SS PAO ATF & still need to know my wear rates are way down before I use it. Tempting.
I'm really curious to what others that use the same ULV will experience, I'm hoping mine isn't an edge case. I have a bunch of friends and family that would gladly pay $20 for a range boost on their Gen 1 Leaf :D
Of course I'll probably be the one doing the actual change for them, but it might be a good way to collect a lot of samples for laboratory analysis. :)
 
i have only driven a couple hundred miles so far with the ULV, commute is now only a once a week type of thing. My results with the ULV are that my average bumped from 3.5 to 3.9, but some of that bump is from the fact that temperatures here in the NW have jumped a solid 10F right when i did the fluid change - from 40-50F into the 50-70F in the last two weeks. 3.9 is what i saw last summer during the warm season, so if my average creeps over 4 while driving the way i'm driving, then that is certainly statistically significant. The other variable compared to knight is that i started with redline D6, not the stock Nissan fluid.

The 10R80/10L80 transmission that Ford/GM use and that uses this Valvoline ULV ATF fluid (or similar) in started production in 2018, I am very curious what gear oil other EVs use, like Hyundai Kona, Teslas, Ford MachE, Chevy Bolt.

Marko
 
estomax said:
I am very curious what gear oil other EVs use, like Hyundai Kona, Teslas, Ford MachE, Chevy Bolt.

Kona, Niro, Soul-EV, Ioniq, all EVs from the Kia-Hyundai kingdom: GL-4 70W spec gear oil, which I think is about KV100 6, like Dexron VI & Mercon LV, & Redline D6 & Amsoil SS Fuel-Efficient type, certainly more viscosity than Nissan Matic S which is 5.2 (and way over Valvoline ULV, Mercon ULV, Dexron ULV which are all about 4.4.)

Tesla: Dexron VI kv100 about 6. .. Tesla Model 3 has a cool spin-on external oil filter for their gearbox, jealous of that....

Ford Focus Electric: Mercon LV kv100 6 (same in Ford C-Max & Fusion Hybrid prius-like gearsets).

Mach E: It's complicated. They use Mercon ULV kv100 4.5 in the standard-base rear drive unit, and they use a THICK GL-5 75w-85 fluid in the front gears if you option to AWD. (GL-5 thick stuff is only used when you have to serve a Hypoid right-angle gear master.)
https://www.macheforum.com/site/threads/how-to-change-your-oil-transmission-oil-gear-oil-yes-thats-a-thing.5395/

Chevy Bolt: GM spec'ed a slightly lower viscosity (still higher than Matic S !), longer-lasting type ATF fluid of Dexron HP kv100 5.7. The first model year of the Bolt used Dexron VI kv100 6.

BMW i3: I looked into this a while back, and it does look like they use something quite thick. ..... Could be, they simply chose to use narrower gear teeth faces & wanted higher visc stuff to counter the higher teeth pressure. BMW is a bit mysterious; teutonic riddles in the Black Forest. ;)
They even got very strange the way they deleted the oil fill port from the gearbox casting itself (deleted the friggin' fill plug!), sealed for life, but only on 2016-current BMW i3's. Nobody can explain that. What's the German phrase for "WTF"?
 
DougWantsALeaf said:
That is a huge improvement. Definitely worth a try. Is that much energy lost in the gearbox?

There are two sets of gears in the Leaf gearbox, and spur gears are 95%+ efficient, so the increase on paper from changing out the fluid can't be that much. But this is why we are doing empirical testing, to see what it really is :)

Technically we could put some more 'lab test' like numbers to this experiment by finding someone who has the gearbox out of the car and can put an electric motor on it's input shaft to measure how many watts it takes to 'idle' it at some low speed. Could even test the difference between stock and ULV gear oil that way to get a more number backed answer.

voltamps, that is very interesting on the other ev manufacturers gear oil choice. Now just give knight and me 6+ months to put some miles on here and then see if our fill plug has a ton of debris on it or not :D
 
Got my Blackstone Laboratories report today. This is the analysis of the gear oil that came out of my 2020 Leaf before I put in the ULV. You can imagine, it was still in good shape since it was still fairly new, but it did have some of the gear break metal bits floating around. Read for yourself below, picture of report attached. Blurred out private information, so feel free to share the image anywhere else that you want. :D

lCIDB4z.jpg
 
For comparison, find my old 2013 Leaf Oil Change report here (near the bottom): https://mynissanleaf.com/viewtopic.php?f=38&t=25076&start=120
 
DougWantsALeaf said:
It would seem if there was 8-9% to be had, the gear box with the 9ld oil should be much hotter after a drive than after the change to the ULV oil.

That's what seem counter-intuitive about it. My guess is that the same cooling system that circulates for the motor, power controller, etc. is cooling that entire connected block. The gear oil, being so close, would also be getting this cooling benefit. Since from I gather, the cooling system kicks in at 100F and my measurements of gear oil temperature after hours of driving in hot, sunny weather seem to indicate something is controlling the temperature. This is the video I posted at the other topic (below), but basically the gear oil was probably close to +118F before I had to spend a few minutes to get the engine shield off and put the temperature stick directly into the gear oil. I was expecting the temperature to be high, like around +180 F. If the gear oil is being cooled, be indirectly, that still means the wasted energy is having to be carried away by the system. Since the ATF that Nissan uses is intended for ICE vehicles, it has to reach a certain temperature (200F) to reach it's lowest viscosity for smooth movement. The gear oil in the Leaf never gets hot enough and thus, remains basically, thicker. Since the friction can't build up enough to get it hot enough for optimal temperature, that might mean part of that wasted energy is being carried out by the coolant system in the Leaf. It's like pointing an Air Conditioner at a Heater, you're just wasting energy to cancel out the two if the intention was to warm up the room.

Now, given if all of that is true, the gear oil never gets hot enough and the coolant system is keeping it chilled, the introduction of a ULV that is thinner at lower temperatures means this fighting effect will happen less, which means less wasted energy. As others have pointed out, it might come at a cost to the gears not lasting as long, but the effect might be so small that the increase in range is worth it in the long run.

https://www.youtube.com/watch?v=PPjH2IXBJ04
 
This was some great info posted by Voltamps, so I think it would be handy to have it in this topic since it seems relevant to the discussion.

voltamps said:
Thanks for doing all that. Should be good fluid in there. 122F (little hotter due to a few minutes) = 50C does seem cool for a gearbox. If that's correct, the worst day near Phoenix in July might get it to (??) about 70C, still not terrible.

There are notable differences in the kinematic viscosity (kv) over that temperature range.
Your 50C column below indicates about 4 cSt difference between the Valvoline ULV & Nissan Matic S, others listed for comparison:
Ko0r5YR.jpg

https://www.widman.biz/English/Calculators/Graph.html

(The enthusiast-popular Redline D6 viscosity curve is identical to the Amsoil SS above, both have kv40 & kv100 the same and r extremely close.)

Currently, no EV in the industry uses gear oil thinner than Nissan Matic S at kv100 5.2.
Chevy Bolt is close using Dexron HP at kv100 5.7. Tesla uses Dexron VI at around 6. Ford specs their Mercon LV at 6.
It does depend on the shape of the gear faces & resulting pressure. Nissan engineers, guessing, could have gained a tiny bit of range specing some ULV fluid. Maybe look for that in future EVs trying to get that last mile of range to market.
 
DougWantsALeaf said:
Any risks by moving the ULV gear oil?

I believe you meant moving to the ULV gear oil? Currently, the risk is that it is bad for the gears. Only 2 of us at this forum are doing it so far. I intend to change out my gear oil again this summer so I can check the magnetic plugs and fluid for signs of metal wear from the gears. I will also send a sample to Blackstone Laboratories for an analysis. Estomax wants to check their gear oil in 6 months for the same reason. If either of us suspect something doesn't look good, we can always change back to some thicker gear oil and consider it a lesson learned for science. :)

I suspect, looking at the chart provided by Voltamps, the gear oil never gets hot enough to truly be as thin as it could be and thus as the lower temperatures the Leaf operates at, still stays a little thick, just not as thick as the standard stuff that Nissan uses. That might be where the range savings are coming from.
 
One thing we've seen, is that if you keep your foot out of it at launch, it is easier on the gear teeth wear.
The other thread had somebody who bought a Leaf used for tens of thousands of miles at a Driving School where they baby it. Original Matic S factory oil, and the magnets were very clean, not much steel getting worn off into the fluid.

Personally, I like to hit it hard at launch. Bad but fun habit. __ Maybe I'm better off sticking with the slightly thicker Amsoil SS ATF (like Redline D6) just because I abuse it.
Think about how we get full torque at/near launch with electric motors, unlike ICE engines, meaning gear tooth forces & pressures are higher, while at the same time the gears are running at low RPM. RPM proportional to speed. This pushes the infamous Sommerfeld Number low, especially when combined with a warm gearbox, meaning metal-to-metal Boundary Lubrication on the Stribeck Curve.
 
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