Posts: 367
Joined: Fri Jun 14, 2013 5:54 pm

Transaxle Oil

Well, I haven't managed to totally destroy my I-MiEV yet so I am off on another mission. The Transaxle in the I-MiEV uses ATF (automatic transmission fluid) as it's lubricant. I was digging through boxes of junk I have around and came across a couple of bottles of transaxle oil for use in the GM EV-1. It's a really low viscosity oil---about like water. The label says "Synthetic Motor Oil--For electric vehicles--Reduces viscous drag--Increases vehicle range". It was GM P/N 12371288 which is no longer available (except I found some in Italy for 30 euros a pint--maybe). I don't know who made this stuff, but if it worked in the EV-1, it should work in the I-MiEV. If it doesn't, I have a spare transaxle just in case. I don't know how much it will affect the range, but every little bit helps. Do enough minor changes and it might actually start to increase range.
Posts: 356
Joined: Tue Jun 19, 2012 11:26 am
Location: Maynard, MA Eaarth
Contact: Website

Re: Transaxle Oil

I think you need to use the oil that the gear set is designed for. This *might* make a tiny (<1%) or it could ruin the unit.

A single aero mod would save you 10-15%.
Sincerely, Neil
Site Moderator
Posts: 3101
Joined: Thu May 10, 2012 3:55 pm
Location: Biloxi MS

Re: Transaxle Oil

NeilBlanchard wrote:A single aero mod would save you 10-15%.
If you got an extra 10% to 15% from every aero mod, it wouldn't take too many to double your range . . . . would it?

I could see that removing the outside mirrors would clean up the aero a bunch . . . . but would it really increase the range by that much? Where so we find these numbers?

I agree on the transmission oil - I'd stick with the recommended lube (maybe go with synthetic ATF) because there's little to be gained, but much to be lost

2012 iMiEV SE Premium, White
2012 iMiEV SE Premium, Raspberry Metallic
2012 iMiEV SE, White
2021 Volkswagen ID.4 Glacier White Metallic
2014 Ford Transit Connect XLT SWB wagon
2006 Itasca Navion Sprinter Motor Home
Posts: 367
Joined: Fri Jun 14, 2013 5:54 pm

Re: Transaxle Oil

Already changed to the EV1 oil. Ran it 75 miles per hour on the freeway for 20 miles and turned around and did it again coming back. No ill effects. Transaxle nice and cool (considering) and no leaks. Hey, it's not for everyone, but I had the oil and I have a spare transaxle if I mess it up. I have had the I-MiEV transaxle apart and a S10-E (same as EV1) also apart. Very similar in design, gear diameters (therefore pitch line velocities), and number of reduction stages. I figure if GM went to the trouble to come up with this special expensive oil (and I had some) why not. Worst case, the transaxle will catch fire, lock up and burn the car to the ground on the side of the freeway---but more likely nothing will happen. It's like going to LED bulbs, a little expense, a little gain. In this case no expense and a little gain I am sure. Aero mods are the best thing on this car and that might be next---the mirrors look like they should be gone replaced by cameras. I am not a hypermiler but I am having fun with the car :P !
Posts: 1
Joined: Thu May 18, 2017 7:48 am

Re: Transaxle Oil

Hi Siai47, i see this old post on gm pn 12371288 ev1 gear oil. wondering if you have any more of the oil? i am looking for some and have not yet found an nos source. pls advise. thx. (1.75 qts)
Site Moderator
Posts: 4168
Joined: Thu Dec 15, 2011 5:47 am
Location: Silicon Valley, California

Re: Transaxle Oil

Mievo's transaxle failure Seized Gearbox :shock: gave me a jolt as, once again, I had procrastinated and not checked nor changed the oil when I recently had Mitti up on jackstands when replacing the tires. Just ordered two quarts of Amsoil Synthetic Signature Series Automatic Transmission Fluid, which is probably overkill in our minimally-stressed i-MiEV. Just under $30 for two quarts on EBay, including shipping. It's specs say they meet/exceed the Mitsubishi DiaQueen SPIII SP3 Transmission Fluid requirements.
EVs: Two '12 Wht/Blu SE Prem., '13 TeslaMS85, three 156v CorbinSparrowsLi(NMC), 24v EcoScoot(LiFePO4)
EV Conversions: 156v '86 Ram PU, 144v '65 Saab96, 48v1kW bike
RIP(2021) ICE: Orig.Owner '67 Saab96V4, '88 IsuzuTrooper; '76 MBZ L206D RHD RV
Posts: 446
Joined: Wed Jan 28, 2015 1:52 pm

Re: Transaxle Oil

JoeS wrote: It's specs say they meet/exceed the Mitsubishi DiaQueen SPIII SP3 Transmission Fluid requirements.
If one were at all concerned about Warranty issues down the road :). I got the real deal - Mitsubishi DiaQueen SPIII SP3 Transmission Fluid. I got two of them through Amazon for $12.88 each shipped free from White Bear Mitsubishi online parts, in Minnesota. Coincidentally this is the same dealer that I bought the car from new!

(July) 2014 cool silver ES, acquired new 4/2015 (40.9ah at ~34K miles)
(Aug) 2014 Labrador Black Pearl ES, acquired new 3/2016 (39.7ah at ~20k miles)

Return to “Driving the iMiev - Range - Energy Efficiency - Operating Cost”