Reduction Gear Oil Change - Benefits for Range

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SageBrush said:
I followed @voltAmps suggestion and chose by standard ... and ended up with the Walmart sh1t -- aka SuperTech Dexron - VI, Mercon LV, approved for Matic-S substitution. How bad can it be ? :lol:
Good choice. kv100 5.8 , Warren Distribution, Omaha NE, blends it from Lubrizol's standard Dexron VI additive package & I think the base oil comes from Exxon-Mobil, not sure, & they just blend it together in the right proportions. Commodity stuff. Walmart puts their own SuperTech store-brand label on it. Warren & Lubrizol are good companies. Here it is with the MAG1 label on it some stores sell it under: ...
https://mag1.com/products/transmission-fluids/passenger-car-automatic-transmission-fluid/mag-1-low-viscosity-multi-vehicle-transmission-fluid/

If you use Dexron VI in your Tesla, first check to see it is the right fluid these days. They use to spec that, maybe not now (???).
 
voltamps said:
If you use Dexron VI in your Tesla, first check to see it is the right fluid these days. They use to spec that, maybe not now (???).
Ah hell, why did you have to mention the Tesla ?

For now, I'm living under the rainbow where the Tesla filter turns the oil into a lifetime fluid. If reports surface of cruffy oil I'll remember your advice.

Photos of LEAF ATF ... once the gaskets arrive.
 
SageBrush said:
Per this article, the reduction gear is 93% efficient

https://core.ac.uk/download/pdf/84757619.pdf

For OP's data to be correct, the oil change would have to improve gear efficiency to 115%

When I read the document you linked, it showed 90% - 93% efficient. But not to nitpick :)
It did mention that the assumption was made against a 100% efficient gear system, but doesn't mention anything about temperature or what viscosity fluid it is operating in. I don't know if that means that there will be further loses to account for the fluid it sits in or if it operates in a cold or high temperature. At least thought it is a good starting point when doing the mental math about what benefit, if any, the fluid change makes. Thanks for the link!
 
SageBrush said:
For now, I'm living under the rainbow where the Tesla filter turns the oil into a lifetime fluid. If reports surface of cruffy oil I'll remember your advice.
That is true, good point, the big spin-on oil filter probably does make it last 150k miles. Oil filters are usually good at getting all the bigger than 40 micron size chunks out, and the magnets get the rest. I'd only change it on a Tesla Model 3 if it was super-easy to do like the Leaf is.

Frankly I think it's strange the Tesla M3 & Bolt both have oddly complicated gearboxes, with pumps & filters. Why not keep it simple like Nissan did & easy to change every 60k miles? There is the cooling the fluild does in a Model 3 that can do 140 mph, there is that. Guess thats it. The Bolt has no excuse though.
 
voltamps said:
Frankly I think it's strange the Tesla M3 & Bolt both have oddly complicated gearboxes, with pumps & filters. Why not keep it simple like Nissan did & easy to change every 60k miles? There is the cooling the fluild does in a Model 3 that can do 140 mph, there is that. Guess thats it. The Bolt has no excuse though.
I remember watching a Weber State video a while ago showing the Chevy Bolt powertrain disassembled. The oil pump is to load a reservoir where the oil drains via gravity through the electric motor for cooling. The common oil source is recirculated through everything (motor, gearbox, and differential). If I recall correctly they also have a small heat exchanger to a glycol loop with a small radiator & fan for further cooling if needed. Likely one of the most positive attributes of the Bolt is a really robust design for this powertrain. Correct me if I'm wrong, but don't think Nissan uses oil-cooling for the electric motor. The oil is strictly for the gearbox and differential.
 
SageBrush said:
I followed @voltAmps suggestion and chose by standard ... and ended up with the Walmart sh1t -- aka SuperTech Dexron - VI, Mercon LV, approved for Matic-S substitution. How bad can it be ? :lol:

I'm not positive but this may be the spec sheet: https://www.schaefferoil.com/documents/267-205A-td.pdf
As an aside, Peakauto.com appears to sell an oil that is very similar if not identical per https://peakauto.com/wp-content/uploads/2017/01/PEAK-ATF-DexronVI-MerconLV-Full-Synthetic-Trans-Fluid-Spec-Sheet-201905.pdf

$6.6 a quart
Having the same thoughts, cheapest stuff available from Walmart & be done with it. What is so special about Nissan branded Matic-S for a simple gearbox & differential application? Any compatible fully synthetic ATF that meets these newer standards (example...Dextron VI) will likely work just fine. I ran the Valvoline Max-whatever stinky-stuff replacements in my Honda automatics for many years and they didn't come apart like the Honda fanatics predicted. Come on, this is a simple gearbox...
 
voltamps said:
SageBrush said:
For now, I'm living under the rainbow where the Tesla filter turns the oil into a lifetime fluid. If reports surface of cruffy oil I'll remember your advice.
That is true, good point, the big spin-on oil filter probably does make it last 150k miles. Oil filters are usually good at getting all the bigger than 40 micron size chunks out, and the magnets get the rest. I'd only change it on a Tesla Model 3 if it was super-easy to do like the Leaf is.

Frankly I think it's strange the Tesla M3 & Bolt both have oddly complicated gearboxes, with pumps & filters. Why not keep it simple like Nissan did & easy to change every 60k miles? There is the cooling the fluild does in a Model 3 that can do 140 mph, there is that. Guess thats it. The Bolt has no excuse though.

Tesla had some big teething problems early on with the Roadster transmission. Originally they wanted a 2-speed unit but torque caused those to self-destruct. It was at least 3 iterations and multiple suppliers before they had a workable gearbox. And there was some kind of "milling noise" problem with the Model S too. So maybe they embraced the habit of over-designing their gearboxes and drivetrains.
 
This stuff looks pretty thin! http://www.pentosin.net/specsheets/Transmission%20Fluid_ATF%20134%20FE_2017_COLOR.pdf
 
Nubo said:
Tesla had some big teething problems early on with the Roadster transmission. Originally they wanted a 2-speed unit but torque caused those to self-destruct. It was at least 3 iterations and multiple suppliers before they had a workable gearbox. And there was some kind of "milling noise" problem with the Model S too. So maybe they embraced the habit of over-designing their gearboxes and drivetrains.
Interesting info. Hadn't heard that. I guess not surprising since they have mega-torque to handle at low Sommerfeld Numbers. They also need to handle (cool, lubricate) at blazing top speeds, as the Tesla Model 3 gets to 140 mph;, some versions of the Model S get higher, wow, on 1-speed. Should have had it all sorted out in prototypes though.

Makes me think of hard core racers (Lemans 24-hour, etc.), & maybe they dump a little moly in there(??), like I've been tempted to do but am concerned it could defeat the silicone anti-foam additives. "Ford vs. Ferrari" movie had some gearboxes famously melting too.

rogersleaf said:
Correct me if I'm wrong, but don't think Nissan uses oil-cooling for the electric motor. The oil is strictly for the gearbox and differential.
That appears to be true for our Leafs. The motor and electronics are liquid cooled with anti-freeze water/glycol. Power shaft (axle) seals & isolates the motor from the ATF fluid lubricating & cooling the gears & shaft support bearings, along with the spider gears in the differential.

Nubo said:
This stuff looks pretty thin! http://www.pentosin.net/specsheets/Transmission%20Fluid_ATF%20134%20FE_2017_COLOR.pdf
Ravenol T-ULV is still the thinnest ATF around, at kv40 12 & kv100 3.3 but not imported to the U.S. now.
The Pentosin is a Mercedes spec 236.15 with kv40 18 & kv100 4.36.
Valvoline ULV is kv40 19.4 & kv100 4.45 about the same.
(Nissan Matic S is around kv100 5.2, considered the official do-not-go-below point, for some reason. )
 
voltamps said:
Interesting info. Hadn't heard that. I guess not surprising since they have mega-torque to handle at low Sommerfeld Numbers. They also need to handle (cool, lubricate) at blazing top speeds, as the Tesla Model 3 gets to 140 mph;, some versions of the Model S get higher, wow, on 1-speed. Should have had it all sorted out in prototypes though.
I think it was Elon Musk who added background to that story: the Roadster Gen 1 was only built in the 1 - 2 thousand copy scale, Tesla did not have the requisite in-house expertise to build the gear-set they needed, and Tesla was on a shoestring budget. It all conspired to saddle them with outside R&D way below the expertise level needed for their mega torque application.

That they eventually brought the car to market (and the car is still running around today) is a little bit more than amazing, since it was Lotus level specs (for the time) on a Ford Pinto budget.
 
rogersleaf said:
SageBrush said:
I followed @voltAmps suggestion and chose by standard ... and ended up with the Walmart sh1t -- aka SuperTech Dexron - VI, Mercon LV, approved for Matic-S substitution. How bad can it be ? :lol:

I'm not positive but this may be the spec sheet: https://www.schaefferoil.com/documents/267-205A-td.pdf
As an aside, Peakauto.com appears to sell an oil that is very similar if not identical per https://peakauto.com/wp-content/uploads/2017/01/PEAK-ATF-DexronVI-MerconLV-Full-Synthetic-Trans-Fluid-Spec-Sheet-201905.pdf

$6.6 a quart
Having the same thoughts, cheapest stuff available from Walmart & be done with it. What is so special about Nissan branded Matic-S for a simple gearbox & differential application? Any compatible fully synthetic ATF that meets these newer standards (example...Dextron VI) will likely work just fine. I ran the Valvoline Max-whatever stinky-stuff replacements in my Honda automatics for many years and they didn't come apart like the Honda fanatics predicted. Come on, this is a simple gearbox...

Back in my Honda owning days, it did not even occur to me that a transmission should be maintained so I never changed that oil. Honda is catering to my kind of fool who benignly neglected maintenance. If you actually maintain the part, you can get away with a lower spec. The LEAF is a similar story but even more so because it is easy to replace, cheap to replace, and the car accumulates few miles per year, and for our car, easy ones at that**. In the very unlikely event that we still own the car 30k miles from now, I'll buy another $13 worth of ATF.

My joking about walmart quality aside, I think @voltamps is right that ATF manufactured to a Dextron VI/Mercon LV standard is reasonable stuff. In fact, it meets car manufacturer specs across a wide range of cars. In the future a new wave of awesome oil may be offered and customers may have to choose cost Vs quality but for now a decent store brand can match up well with name brands.

**My wife is the main driver. I doubt she breaks 10 seconds in her 0 - 35 mph drag driving. I know I get yelled at if I floor the go pedal or if she can feel acceleration. Maybe 0.3 G on an aggressive day.
 
rogersleaf said:
Having the same thoughts, cheapest stuff available from Walmart & be done with it. What is so special about Nissan branded Matic-S for a simple gearbox & differential application? Any compatible fully synthetic ATF that meets these newer standards (example...Dextron VI) will likely work just fine. I ran the Valvoline Max-whatever stinky-stuff replacements in my Honda automatics for many years and they didn't come apart like the Honda fanatics predicted. Come on, this is a simple gearbox...

EVs have very simple gearboxes, however the demand here is the very high RPM that the motor (and hence the input gear) operates at. The 2018 LEAF indicates a max motor RPM of just under 10K RPM, but Tesla motors are operating at much higher yet, in the 18K RPM range. The fluid is not trivial at all :) The torque on this primary gear is actually not that high relative to an ICE motor. It's the reduction that is giving you all that torque.

The oil needs to keep metal from contact at pretty high torque on that final gear, yet do the same at very high RPM on the input. This is why you see oil pumps in use on the Tesla system where bearings require more direct lubrication, versus just splash lube on the Nissan case. I'd rather have less power, with greater simplicity.

Frankly I was surprised that the final drive oil was so thin on the LEAF as I'm quite accustomed to 75w oil being used in differentials on most cars I've worked on. These ICE diffs operate at far lower RPMs, so it's obviously the EV motor drive RPM that is dictating the use of highly engineered fluids. The Audi A3 TDI that I serviced recently had some pretty interesting 75W fluid used both for final drive and DSG trans operation. It also took a laptop and $700 of software to service correctly....249 ft/lbs of torque from that engine at 1200 RPM. So again, it's a bit weird to be putting such low viscosity fluid in what is essentially a differential.

Nissan Matic S - Kinematic Viscosity @ 100°C cSt ASTM D445 5.2

Typical 75w-90 Gear Oil - Kinematic Viscosity @ 100°C cSt ASTM D445 14.56
 
LeftieBiker said:
So...because Tesla motors run at high RPM, it's important that Leafs be run with gear oil that can handle that...?

No, that is why Tesla includes forced lubrication
 
DougWantsALeaf said:
So Denwood, are you saying Nissan is actually already pushing the envelope with the stock gearbox oil?

That was true in 2011. Nowadays the ATF the LEAF specs is in widespread use.
 
denwood said:
EVs have very simple gearboxes, however the demand here is the very high RPM that the motor (and hence the input gear) operates at. The 2018 LEAF indicates a max motor RPM of just under 10K RPM, but Tesla motors are operating at much higher yet, in the 18K RPM range. The fluid is not trivial at all :) The torque on this primary gear is actually not that high relative to an ICE motor. It's the reduction that is giving you all that torque. ...

I've also heard it said that the "slew rate" is also critical. I.e., how fast the torque is applied. The idea being that an electric motor can apply the force faster than the metal can transfer it into the drivetrain's inertia, causing local deformation and failure. Analogous to an ICE vehicle where someone revs up and "dumps the clutch".
 
SageBrush said:
I think it was Elon Musk who added background to that story: the Roadster Gen 1 was only built in the 1 - 2 thousand copy scale, Tesla did not have the requisite in-house expertise to build the gear-set they needed, and Tesla was on a shoestring budget. It all conspired to saddle them with outside R&D way below the expertise level needed for their mega torque application.

That they eventually brought the car to market (and the car is still running around today) is a little bit more than amazing, since it was Lotus level specs (for the time) on a Ford Pinto budget.

As I recall, a few early Roadsters were delivered with the 2-speed box, with recommendation to the owner to stay in 2nd gear and a promise that Tesla would replace the gearboxes for free as new units became available.
 
This is an interesting discussion. I planned to change the gear case fluid at 30k miles on my 2019, but I have projects going which keep me from using my lift so I guess it will have to wait (hopefully change at or before 36k miles). I will use Matic S to keep the warranty intact since I can buy a couple quarts for a reasonable price at the dealer. I will be watching oil test results from others for the low viscosity fluids and may switch after my warranty expires if the test results for metal content look good.
 
DougWantsALeaf said:
So Denwood, are you saying Nissan is actually already pushing the envelope with the stock gearbox oil?

I'm assuming the Nissan engineers have done their homework :) What I will say is that I would stick to oils that match or exceed the Matic S spec. For sure, in about 25 years of wrenching on cars, I've never seen such low viscosity oil in a gear box that is essentially a differential. So would I go lower viscosity than the Nissan Matic S spec? Nope. Switching over with oil testing like Gerry suggested is a good route to go if you're planning on pushing the viscosity envelope. Honestly though, the gains to be had here are marginal at best. You'll do better just checking tire pressures regularly.
 
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