Electric vehicles (EVs) generally have a much simpler transmission than traditional gas cars. So much so that usually very little maintenance is required. Even so, changing the reduction gear oil is a simple project that can net about a 10% improvement in efficiency. I recently changed the reduction gear oil in my 2018 Nissan Leaf, and after one ski-trip, I seem to have used fewer electrons, moving from 5 km/kWh to 5.9 km/kWh, easily justifying the $150 I spent.
The service manual for the 2018 Nissan Leaf does not require a replacement of the reduction gear oil at regular intervals, instead every 12 months or so, an inspection is recommended. Thus, if you have an older Leaf, which my 2018 is getting to be, it might be worthwhile to replace the reduction gear oil. Some chatter online, suggests some efficiency improvements might be had (source, source, and source).
One of the above references dives into a lengthy discussion on which oil to use. I settled for “Nissan Matic S ATF” which I got from a local dealership, along with the two replacement compression gaskets you will need. You need to get “a quart and a half”, so I got two quarts, figuring a little extra would help compensate for poor aim, spills etc. It can be argued that some of the lower viscosity lubricants might prove a better choice, particularly at lower temperatures when viscosity is higher. Regardless, I should point out that the reduction gear in a “typical” electric car, is about 95% efficient (source), thus regardless of what oil you choose, even a 100 % perfect transmission would not bump your range by much. Hence I decided to stick with Nissan Matic S.
While I could have done this myself, I felt an obligation to educate my local garage, which deals mostly in conventional older gas cars. Plus they do offer excellent service, are very conveniently located and charge very modest prices. So I paid about $70 to my Nissan dealership for the Oil (and gaskets), along with $80 in labor to my local garage.
With the oil changed, for “science” it seems I had to go skiing. Recall from my previous winter’s Blue Mountain Ski trip (source), I saw an overall trip-efficiency of 5 km/kWh with my ski-rack installed. Post reduction gear oil change, I tried to re-create the trip as much as possible, choosing a similar route and trying my best to keep speed to similar level, and love and behold, I get 5.9 km/kWh, with the same ski-rack installed, and loaded with the same skis.
While it is tempting to attribute the 0.9 km/kWh increase in efficiency to my reduction gear oil change, I must point out that this is far from a perfect experiment. I’m guessing some of it is, but I recall quite the cold snap on my last years Blue mountain trip, plus I did get stuck behind a feed truck doing a very modest 70 km/hr on this one. Both of these could easily have had a much bigger impact than the reduction gear oil, but my 0.9 km/kWh improvement is not too far off from what others have reported after changing the reduction gear oil (0.8 km kWh source, 0.5 km/kWh source).
Should these efficiency gains hold on my next Tremblant run (see this post), I might manage to drop by travel time from 10 hours and 30 minutes to 10 hours and 10 minutes, not bad given the $150 required to make this happen, certainly cheaper than upgrading to a Nissan Leaf plus.
Electric car adventures 