How To: Reduction Gear Oil Change

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voltamps said:
All would be fine in the Nissan Leaf, except the long term gear teeth and bearing wear in our reduction gearbox could be reduced a few thousand miles if you go to the thinnest in the group, the ULV stuff:

Redline D6 ATF: kv100 6.3
Amsoil Signature Series Fuel Efficient ATF: kv100 6.3
Valvoline MaxLife™ Multi-Vehicle ATF full synthetic: kv100 5.9
Mobil 1 Synthetic LV ATF HP ATF: kv100 5.7
Idemitsu Nissan Matic S: kv100 5.2
Valvoline ULV ATF full synthetic: kv100 4.5

Yes lower viscosity does mean more EV range. That would work.

Durability is a concern with the ULV fluids though.

Thank you for posting this summary. I have a case of the AMSOil Fuel Efficient ATF that was left over from my Titan. I plan to use that in the Leaf. I was surprised to see the viscosity number for it was higher than Matic S, so I checked on it. According to the PDF link below (top of page2), the KV100 number is 5.8, not 6.3.

https://amsoilcontent.com/ams/lit/databulletins/g3190.pdf
 
HRTKD said:
the KV100 number is 5.8, not 6.3.
https://amsoilcontent.com/ams/lit/databulletins/g3190.pdf
Not quite the same fluid you posted the link to.
Does your stash have the words "Signature Series" on the label? If so, it is the better all-PAO formula (longevity) with kv100 6.3.
If it matches your link (Amsoil OE Synthetic Automatic Transmission
Fluid), then it's fine to use, and the kv100 5.8 will give you slightly less viscous drag in the gears, & more range, & fully compatible with Nissan Matic S, but it isn't as long lasting as Amsoil's Signature Series fluids.
 
knightmb said:
I am curious if the gear box ever reaches 100 C inside to produce the temperatures needed to make the oil thin enough to reach the rated viscosity numbers. My guess is that it probably doesn't
The viscosity curve at all operational temperatures will be lower with the Valvoline ULV thin stuff.

Viscosity chemistry-physics says that if you plotted the viscosity at temperatures say from 100C down to -25C (very cold), the Valvoline ULV thin stuff will be thinner for every temperature point. Guessing an operational driving gearbox temperature of around 80C, the difference in viscous drag will be even greater than at 100C.

You're likely right, our Leaf gearbox probably doesn't reach 100C. Stating kv100 visc values as a property of the liquid merely tells us about the physics, that's all its good for in this case.

I read the internal temperature on a fixed-gear planetary gearset hybrid system on a ForScan phone app (ELM327 OBDII) a few years ago, a similar gear situation as our 4-gear 1-speed fixed set in our Leafs, and it would get to about 185F (85C) tops. I'd expect the Leaf to be somewhere around that on a hot day, highway driving, although heat transfer to the air thru the case is different. It's a reasonable comparison.
 
voltamps said:
HRTKD said:
the KV100 number is 5.8, not 6.3.
https://amsoilcontent.com/ams/lit/databulletins/g3190.pdf
Not quite the same fluid you posted the link to.
Does your stash have the words "Signature Series" on the label? If so, it is the better all-PAO formula (longevity) with kv100 6.3.
If it matches your link (Amsoil OE Synthetic Automatic Transmission
Fluid), then it's fine to use, and the kv100 5.8 will give you slightly less viscous drag in the gears, & more range, & fully compatible with Nissan Matic S, but it isn't as long lasting as Amsoil's Signature Series fluids.

Thanks! I used to buy a bunch of AMSOil products so I should have known to look for the Signature Series stuff. This prompted me to look at what my inventory really is. Unfortunately, I don't have the fuel efficient product, just the regular multi-vehicle ATF and not Signature Series. I now remember that I sold off the last case of fuel efficient ATF to one of the Titan guys. Oh well, it's paid for, so I'll use it. The transfer case in the F-350 is going to to be happy with the frequent fluid changes.
 
voltamps said:
I read the internal temperature on a fixed-gear planetary gearset hybrid system on a ForScan phone app (ELM327 OBDII) a few years ago, a similar gear situation as our 4-gear 1-speed fixed set in our Leafs, and it would get to about 185F (85C) tops. I'd expect the Leaf to be somewhere around that on a hot day, highway driving, although heat transfer to the air thru the case is different. It's a reasonable comparison.
I'm curious as well, I'm going to do about an hour of city/highway driving (temperatures are already 80s F and above here) and then pull up to my driveway and take a temperature reading of the current fluid in it with a stick probe (there is an extra bolt on top that can be taken off for access to the fluid, found that out on the first fluid change) just to see how hot the fluid has become before I do the change that day.
 
Look what came by delivery today! (a week early!) So, today it is 85F and I've already been driving my vehicle around for 3 hours, so I'll do another once around the city for about 30 minutes and come back to measure the gear oil temperature, then change out the existing gear oil fluid with the new stuff!

PvZbCqN.jpg
 
excited to see this experiment, i ordered 2 quarts too, so hopefully i'll just copy you shortly. Would be nice to see a few % better efficiency (and power in theory too, harder to measure that though).
 
Ok, first part, took the temperature of the gear oil after 3.5 hours of driving. It took me about 5 minutes from pulling into my driveway to get the cover off the bottom and open the plug to stick the gauge in. I couldn't get into position to really get a picture, so I made a short video to show. I already knew when I put my hand on the transmission that it wouldn't be a very high reading :lol:

Video Description:
3.5 Hours of driving both highway & city, temperature outside was 85 F and sunny, so the pavement was quite hot. I pulled into my driveway and about 5 minutes later, got the plug open to stick in a temperature gauge to measure the temperature of the gear oil.

Came out to about 117 F , that was very surprising to me! :shock: :eek:
My guess is since the coolant system in the Leaf comes on at 100 F, I would imagine the whole thermal mass isn't going to get hot because of the active cooling.

https://www.youtube.com/watch?v=PPjH2IXBJ04
 
I'm not surprised at that color. None of the fluid changes in my transfer cases over the years have produced nice, clean looking ATF like you see in the transmission.
 
estomax said:
nice handwashing temperature :) that oil looks pretty dark! is it original fill? how many miles?

Marko

Factory fill, had 12,478 miles when I changed it out, yeah it looked a lot darker than I thought it would since the vehicle isn't even a year old yet. :?
 
A picture of the plugs before I put them back in, looked about like the ones I changed on my 2013, so makes me feel confident that the gears are well broken in by now... :)

YBuapir.jpg
 
i hope the car is charging while you do this so you can do another 3 hour drive and get us efficiency results shortly :D
 
Well, the charging cable would be in the way, otherwise I would have ;)

But... I regret that I did NOT make a video of how the gear box sounded *before* I did the change because it is so quiet now, it's almost scary. For reference, if I drive the vehicle with all the windows up and no AC, radio, etc. you can hear the VPS sound when driving below 20 MPH and the gear box whine, especially if coasting down a hill with regen going. You drive the Leaf long enough, you get accustomed to that sound, hearing both of them at low speed. I did a couple laps around the some empty city streets and hills, the first thing I noticed, I couldn't hear the transmission whine. I first I got worried like, uh oh. I pulled over and used Leaf Spy to disable the VPS sound because I couldn't hear the whine anymore. So, did some more up and down hills and could *finally* hear just the slightest whine from the gears. So, I felt better, but also it was so quiet, it had me worried :lol: Anyway, I turned the VPS back on and well it's all I can hear now, no gears, will take a little getting used to...

As far as efficiency difference, that will take longer and many days of data. I have plenty before the change, just need to follow up on the same long routes and record what I am getting (better or worse than before) and I'll report back here. I don't expect some amazing improvement, maybe only as good as I got with my 2013 when I did the fluid change, but the quiet gears really throws me off being so used to the sound. :shock:
 
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.
 
Thanks for the chart, it is great to see the comparison! I wonder if using the ULV in colder climates would have any benefit since it seems the gear box would never really "warm up" enough, I wonder if it has some cumulative effect on reducing "winter" EV range (other than having to run the heater to keep warm and using a lot of power)? So many questions, so little time to experiment! :D
 
knightmb said:
I wonder if using the ULV in colder climates would have any benefit
I'm not sure by how much either. The viscosity difference of say, the Amsoil SS vs. Ravenol ULV is kind of big, even at room temperature 20C (68F), and it just continues to diverge apart as it gets colder.
 
The gearbox runs cooler with thinner oil. ... (Up to the point when it's too thin there is excessive metal-to-metal teeth surface friction, at which point it will run hotter with possible thermal runaway.) Running cooler means less wasted energy, more EV range.

Here is a screenshot from oil running inside gearbox similar to our Leaf's, with clear plastic cover:
Jm9boiP.jpeg


From this youtube video:
[youtube]https://www.youtube.com/watch?v=UnLzm1S0Ly0[/youtube]

Leaf gearbox:
DSC03720.JPG
 
Great video link to see the oil in action. Thinking about it; in an ICE engine, this would be running all the time to feed the automatic transmission at the minimum RPM. In an EV, it would only spin when driving, so stop and go traffic would be time for it to actually stop circulating and I suppose even cool down a little until you start to drive again. So, in theory, cold driving means you have to constantly *spend* energy to keep the oil warm (so the viscosity remains low enough not to fight it when spinning) and it in effect, it's like having another "heater" running during the winter time, be it using much less power of course, but still having to spend energy out of the battery none the less. When running the heat-pump during the winter time, you are basically blowing colder air directly on it from the coils up at the front of the vehicle. I wonder if that is making kind of a feedback loop where the oil needs to stay warm but is constantly being cooled, so it takes more battery power to push through the oil and warm it up, etc. Brain will process that in the background for a while... :ugeek:

This was a good read in the spirit of these thoughts...
https://www.machinerylubrication.com/Read/28956/lubricant-viscosity-index
https://www.machinerylubrication.com/Read/30093/cold-temperatures-lubricants
voltamps said:
knightmb said:
I wonder if using the ULV in colder climates would have any benefit
I'm not sure by how much either. The viscosity difference of say, the Amsoil SS vs. Ravenol ULV is kind of big, even at room temperature 20C (68F), and it just continues to diverge apart as it gets colder.
 
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