2011-2012 reduction gear in 2013 leaf (efficiency gain)

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ruly1000

Member
Joined
Dec 20, 2016
Messages
8
I have a 2013 leaf with what sounds like a bearing noise in the reduction gear. I am looking at replacing the transaxle with a used one from a salvaged Leaf. The reduction gears for the 2011-2012 MY have a different slightly taller gear ratio than the 2013+ MY reduction gear. Can I replace the reduction gear (the whole unit) in my 2013 with one from a 2011-2012? The reason I am considering this is since I have to replace it anyway might as well go with the slightly taller ratio for slightly better efficiency (I don't care about torque). Is the only difference between the 2011-2012 and the 2013+ the gear ratio? Is everything else plug and play (same housings / bolt patterns etc.)? They look identical in pictures online, but of course maybe they are not. I called a salvage parts dealer and they say the "fitment" is different, but they are only looking on their computer that says the are not the same, but I already know that the gear ratio is one difference. If that is the only difference then I'm good to go. Anyone know if it will work?
 
I doubt they cared about compatibility. The motors aren't even the same between the two gens. '11 and '12 Leaf used EM61 while '13 onward use EM57.

https://web.archive.org/web/20150326074117/http://saegtl.org/ev/data/uploads/ev-content/gtlev_tp_2014-01-1879.pdf was on the motor changes. There was also https://web.archive.org/web/20160219091336/http://articles.sae.org/11993/.
 
The exploded views are drawn such that the motor and reduction gear housing shapes appear different between the 2011 and 2015 service manuals I have. The difference in ratio is only 3.2% so you can gain more than that with one size larger tires (which is what I did with both 2015 and 2019).
 
https://openinverter.org/wiki/Leaf_gear_box claims "the input splines are the same across both the em61 and em57 motors, but the bolt pattern is different. you can not use a em61 motor with a gen2 gear box and vise versa. "
 
Keep in mind the powerband and rpm vs. efficiency aren't anything like an ICE engine. Efficiency gains from a taller gear are likely to be minimal if any.

1cR9AUn.png
 
OTOH, when you look at performance, you don't lose as much acceleration, and - IF you can defeat the speed limiter - you get more speed. ICE cars have to deal with much more finicky-ness in the power delivery.

Uh Oh, I feel another anecdote coming on... well, it's at least related to the above. When Volvo offered the P1800S sports car, you could get two versions of the final drive: a 4 speed plus electric Overdrive unit, with the 4 speed's differential geared lower so the OD felt like just shifting into a 5th gear, or just the 4 speed, with a higher geared differential to compensate for the lack of that "5th gear." While most people wanted the nifty overdrive that let you cruise calmly at 90MPH all day, the plainer 4 speed would easily outrun the fancy version, topping out at 120 MPH, vs the OD-equipped version's 110-115 MPH. Why? Because for reasons that have never been explained to me, overdrives (at least in cars) seem to never, ever, be able to reach the redline, even when 1:1 final drives easily can. One of life's little mysteries, I guess....

The above anecdote has been brought you by Old Age. Old Age, that time at the end of life when you finally figure out what you should have done right when you were young. ;)
 
My first car was a 1980 Dodge Colt (really a Mitsubishi) with a twin stick shift. It basically was an 8 speed as it had an overdrive ratio for every gear. It was weird and actually a lot of fun!

5.jpg
 
That's a semi truck configuration! The one Big rig I drove had a two speed rear axle, and worked a lot like that. I wonder why Mitsubishi did that??? For a while I drove extra cars for a car hauler, and one of the cars I had to drive for about 30 miles was a Plymouth (Mitsubishi) Fire Arrow. I might have enjoyed the trip, were it not for a messed up carb that meant the car would only run at WFO throttle. IIRC, back then the Mitsubishis were actually older Hyundai designs that they sold to Mitsu when they stopped producing the cars themselves.

Oh, man. There I went again.
 
I didn't realize it shared anything in common with a semi truck! It was definitely an interesting design choice and actually quite a lot of fun...

It also made the most of an otherwise wimpy engine, albeit with a lot of shifting involved :)

It's been a long time, but from what I remember you didn't have to clutch/declutch when shifting the P/E lever, so it was pretty easy to do that on the fly.
 
I drove a full-sized dump truck for my work-study job in college :mrgreen: and I remember it had a split axle and I remember shifting it although I never really figured out what it did or how it worked. I did a lot of trial and error but I didn't know anything about automobiles at the time and just never really figured it out. Sort of like when I drove a 'three on a tree' shifter for the first time. That involved a lot of experimentation too but I did finally master that one.
 
LeftieBiker said:
... While most people wanted the nifty overdrive that let you cruise calmly at 90MPH all day, the plainer 4 speed would easily outrun the fancy version, topping out at 120 MPH, vs the OD-equipped version's 110-115 MPH. Why? Because for reasons that have never been explained to me, overdrives (at least in cars) seem to never, ever, be able to reach the redline, even when 1:1 final drives easily can. One of life's little mysteries, I guess....

https://en.wikipedia.org/wiki/Overdrive_(mechanics)
 
Thanks. I did know most of that, minus many of the specifics for different units. The unit Volvo offered was probably the most complicated of the lot, because it used oil pressure to engage. What I was talking about was what appeared to be a physical or mechanical principle that was evading me. Thinking about it more, though, I think it's more like the erroneous term "escape velocity" that bugged me through most of my life. There is no physical law dictating a specific velocity (or higher) required to escape from a gravity well, (it was essentially an engineering term related to the fuels and rockets in use at the time) and there appears to also be no law dictating that Overdrives can't provide the top speed for a vehicle. It's just that when designing the drivetrains, automotive engineers tend to assign a role to the O/D that usually precludes it from hitting the redline, because it is just too much an overdrive to do it with the power available, not because of the gearing crossing that 1:1 ratio...
 
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