knightmb
Posts: 967
Joined: Mon Jan 12, 2015 7:41 pm
Delivery Date: 26 Feb 2021
Leaf Number: 306291
Location: Franklin, TN

How to burn some reduction gear oil...

Mon Apr 26, 2021 6:02 pm

Maybe not so much a problem / troubleshooting issue since it takes very specific steps to reproduce it, but I am open to feedback to the more mechanical sage wisdom here.

For a background history, I owned a 2013 SV Leaf for nearly 8 faithful years and finally traded it in a few months ago for a gently used 2020 SL Plus. The Plus part adds the bigger battery pack and higher power motor (maybe the same motor at more power, don't know?) But... when I first got the vehicle, I had a few opportunities to just full power from 0 to 100 MPH (for science!) and the first thing I always noticed was the smell of burning ATF fluid during the top end of the acceleration. I didn't really think much of it because I can do the same thing in many ICE vehicles with an automatic and have in the past. It just chalk it up to abusing the vehicle. Not something one should be doing everyday as it just wears on the transmission unnecessarily.

Oddly enough, I never could achieve this in my 2013, I guess 80 kW just isn't enough to really stress out the reduction gear in the Gen 1 Leaf. Seems Nissan remedied that problem with the Gen 2 :lol:

So.... the point I'm trying to get to. I've been able to reproduce this a few times now (just the luck of traffic that day and no clear law enforcement presence). I did finally just drive back home and check around motor, gear house, tubes, pipes, etc. Basically looking to see if anything was actually leaking anywhere to make the smell. So far I couldn't find anything, no evidence that anything is coming out from either the gear house bolts for changing fluid or anywhere else. I'm in the middle of a gear oil experiment using thinner oil, but I was able to reproduce this before the gear oil change. Today, I still can reproduce the smell, just takes longer before you start to notice the smell (60 mph before gear oil change vs. 80 mph after the gear oil change).

Anyway... back to the point. Is there a type of "pressure" relief on the Gen 2 Nissan Leaf reduction gear house that would let out burning gear oil? That is the question I was trying to get to. :?

Also... has anyone else tried this (on purpose) and noticed any burning oil smell? :shock:
2020 Leaf SL Plus - (Manufacture Date March 2020)
2013 Leaf SV (8 faithful years of service before trade in at 75,679 miles)
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G3NG4R
Gold Member
Posts: 21
Joined: Sun Mar 21, 2021 7:03 pm
Delivery Date: 20 Mar 2021

Re: How to burn some reduction gear oil...

Mon Apr 26, 2021 7:11 pm

I did a highway ramp pull similar to what you're describing during our test drive last month and don't recall a smell. That was in a 2020 SV+ so the same mechanics as your vehicle. It's just one data point though.

goldbrick
Posts: 1291
Joined: Tue Aug 01, 2017 3:33 pm
Delivery Date: 01 Aug 2017
Leaf Number: 311806
Location: Boulder, CO

Re: How to burn some reduction gear oil...

Mon Apr 26, 2021 7:43 pm

I'd guess there is some sort of breather hole to allow the trans to equalize the inside and outside pressures, for temperature, altitude, etc.

Before reading the other thread I had no idea that gear oil could get so hot. Interesting stuff...

GerryAZ
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Re: How to burn some reduction gear oil...

Mon Apr 26, 2021 10:18 pm

There is a gearcase vent. I frequently use all 160 kW and never notice the smell of burning ATF. I also never noticed it on the previous LEAFs. I will be sending a sample to Blackstone when I get a chance to change the fluid in my 2019 to see how the Matic S is doing--I hope before 36k miles, but need to complete some other projects so I can use my hoist (currently a little over 30k miles). The magnets were really well coated and the Matic S was dark brown when I changed the oil in the 2015 at probably about 60k miles so I think that is too long to wait.
Gerry
Silver LEAF 2011 SL rear ended (totaled) by in-attentive driver 1/4/2015 at 50,422 miles
Silver LEAF 2015 SL purchased 2/7/2015; traded 8/10/2019 at 82,436 miles
White LEAF 2019 SL Plus purchased 8/10/2019

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Nubo
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Re: How to burn some reduction gear oil...

Tue Apr 27, 2021 12:29 am

When my 2012 was new, I did a few max-speed runs and I did notice a smell after a few minutes at sustained top speed. Not quite "magic smoke", but maybe a mild hint of "magic roast". I just chalked it up to baking off some type of volatile residue from manufacture. As time went on I couldn't reproduce it. There's a a coolant overflow of course but it wasn't a coolant smell.
I noticed you're still working with polymers.

dmacarthur
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Leaf Number: 306556
Location: Vermont

Re: How to burn some reduction gear oil...

Tue Apr 27, 2021 3:14 am

0-100 runs have not produced any smells that I noticed..... emphasis being on that last word.....
2015 Leaf sold
2019 Leaf Plus S as of 9/30/19
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Learjet
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Joined: Tue Mar 24, 2020 8:04 pm
Delivery Date: 11 Mar 2020
Leaf Number: 309454
Location: Louisiana, USA

Re: How to burn some reduction gear oil...

Tue Apr 27, 2021 4:12 am

I would think it is the AC drive motor heating up and maybe burning off some production residue.
2019 Nissan Leaf SL Plus
Build Date 2/19...car sat new for 1 year until I purchased 3/20

knightmb
Posts: 967
Joined: Mon Jan 12, 2015 7:41 pm
Delivery Date: 26 Feb 2021
Leaf Number: 306291
Location: Franklin, TN

Re: How to burn some reduction gear oil...

Tue Apr 27, 2021 5:45 am

Nubo wrote:
Tue Apr 27, 2021 12:29 am
When my 2012 was new, I did a few max-speed runs and I did notice a smell after a few minutes at sustained top speed. Not quite "magic smoke", but maybe a mild hint of "magic roast". I just chalked it up to baking off some type of volatile residue from manufacture. As time went on I couldn't reproduce it. There's a a coolant overflow of course but it wasn't a coolant smell.
Same for me, never get any smoke and the only way I can smell it briefly; I had the climate control venting outside air to the top vents (so it's basically pointing right at my face / nose) I can get the smell that way. I know the transmission is actually getting hot because when I did this recently, I pulled over at a gas station to look around the engine area shortly afterwards. I felt the gear house, it was hot to the touch, which surprised me. It wasn't flesh burning hot like an ICE engine, but certainly a lot hotter than the what I measured it before when I got readings of +118 F after some long test drives. I'm starting to wonder if I am just burning off something left from the factory when some of the components get hot enough around the motor, gears, inverter, somewhere?
Last edited by knightmb on Tue Apr 27, 2021 7:48 am, edited 1 time in total.
2020 Leaf SL Plus - (Manufacture Date March 2020)
2013 Leaf SV (8 faithful years of service before trade in at 75,679 miles)
Timekoin - The World's Most Energy Efficient Encrypted Digital Currency

knightmb
Posts: 967
Joined: Mon Jan 12, 2015 7:41 pm
Delivery Date: 26 Feb 2021
Leaf Number: 306291
Location: Franklin, TN

Re: How to burn some reduction gear oil...

Tue Apr 27, 2021 5:49 am

Learjet wrote:
Tue Apr 27, 2021 4:12 am
I would think it is the AC drive motor heating up and maybe burning off some production residue.
I've often wondered if I am smelling ozone production from the motor? The smell reminds me of what a laser copier smells like while running.
2020 Leaf SL Plus - (Manufacture Date March 2020)
2013 Leaf SV (8 faithful years of service before trade in at 75,679 miles)
Timekoin - The World's Most Energy Efficient Encrypted Digital Currency

voltamps
Posts: 148
Joined: Thu Dec 17, 2020 6:13 pm
Delivery Date: 14 Dec 2020

Re: How to burn some reduction gear oil...

Tue Apr 27, 2021 6:14 am

GerryAZ wrote:
Mon Apr 26, 2021 10:18 pm
There is a gearcase vent.
I see it, yes a "Hose Breather", costs all of $6.32 . A picture is at:
https://www.nissanpartsdeal.com/parts-l ... tting.html
Image


Probably not burning the ATF fluid. More like smelling a mist churned up like crazy at high speeds. Increase in gear temperature raises pressure inside.
(BTW, is it safe to go 100 mph in a 3,900 lb Leaf Plus extra-heavy, with 16" wheels? The original Ecopias are H-rated anyway, which helps speed margins, thats for sure.)
Nissan must have plenty of reserve fluid quarts inside to account for some escape over time! Their Maintenance Schedule just says to look for leaks, not check the level, although it's a good idea to at least check the level every 75k miles or so due to escape. Or just change it as some of us have, it's easy.

Anybody know if we have a gearbox temperature sensor available on Leaf Spy or Torque etc.?
I haven't tried any of that yet. I've seen this on a C-Max hybrid tranny in the past. When fluid got too low in that one, or any transmission really, telltale temperature goes up a bit. Guessing our Leaf doesn't have gear temperature available, but certainly coolant temperature, which is sort of indirect, given heat transfer into the aluminum housing I suppose.


GerryAZ wrote:
Mon Apr 26, 2021 10:18 pm
The magnets were really well coated and the Matic S was dark brown when I changed the oil in the 2015 at probably about 60k miles so I think that is too long to wait.
The brown color may be more the Red Dye breaking down than anything else. It could be long-term oxidation though, I'm not sure. .............With the Leaf, the weakness is lack of a fluild filter, although who wants that extra complexity? Metal wear particles circulating in there are the BIG issue, and those twin magnets help a lot. Blackstone shows some iron floating around that never gets attached, or maybe gets freed from time to time, from the magnets. Hard to get it all out.
2020 Leaf SV - sold - I'll get another EV later...Reserved the irresistible Maverick Hybrid, here in a few months
2016 Ford Focus Electric (traded in at 34k miles, 5 years)

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