ATF for Gear Reduction - Ioniq/EV6 (E-GMP EVs) Hard on the Fluid?

[Thugzy]

Decided to change the rear fluid in my '23 EV6 GT early at 23,000kms. Just like i use to do in F150s, id change out my rear diff oil early.

The ATF spec is SP4M-1.

The factory fill ATF came out cloudy and dark purple. Not use to seeing ATF go this cloudy. When i serviced ATs, unless there is an internal issue, the old fluid is usually somewhat clear. I will be sending it out for UOA to compare to new fluid.

I will change out my front fluid. Would be interesting to see if the fluid condition is similar. I mostly drive the car in Eco which disconnects the front drive... I occasionally use GT to blast from a stop for fun.

The OE fluid is very expensive in Canada at $40/L.

These oil brands carry the spec
Valv Multi Max Life
Amsoil Signature Fuel Efficient
Royal Purple Max ATF

I would have been confident to replace it with any of the above, but id like to know what happend to the factory fil before adventuring out of OE fluid.. are the gear reduction boxes hard on ATF? Not sure if a multi spec fluid would be a good idea. UOA & VOA needed to find out...

 

[ctechbob]

Just a WAG on my part. Lots of torque, beveled gears, high speeds, and not a lot of fluid.

Probably a recipe for beating up the fluid.

 

[Thugzy]

Just a WAG on my part. Lots of torque, beveled gears, high speeds, and not a lot of fluid.

Probably a recipe for beating up the fluid.

Just fyi, the sump is just over 3L

 

[JavierH19]

There's no clutches or anything in these. The specified fluid is just whatever they put in other atf's. If you felt like using leftover dexron 3 it'd be fine though of course it'll break down sooner. But again these aren't picky. What jug of atf can you get for cheap new you. Castrol transmax or similar would work fine.

 

[martinq]

If that was mine I would change out the fluid at 1k km, then again at 5-10k to see how it's doing. Basically cut the "severe duty" maintenance cycle to a third until the system cleans up and THEN follow the severe duty maintenance suggestions. Are there any filters or magnets in these gearboxes?

Valvoline Maxlife ATF is easy enough to get in Canada, I usually pay $10 / L unless I can catch a sale.

 

[crashz]

That opaque fluid looks like it may have some moisture in it. Any chance a vent is loose or something?

 

[The Critic]

That opaque fluid looks like it may have some moisture in it. Any chance a vent is loose or something?

That is what SP3 and SP4M typically look like, even in a conventional automatic at low mileage.

 

[crashz]

That is what SP3 and SP4M typically look like, even in a conventional automatic at low mileage.

Ewww! - Well, you'll know when to change it at least. My OCD would have me twitching with that fluid.

 

[Kiwi_ME]

... but id like to know what happend to the factory fil before adventuring out of OE fluid.. are the gear reduction boxes hard on ATF? Not sure if a multi spec fluid would be a good idea. UOA & VOA needed to find out...

Oil looking like that has been a 'feature' of Hyundai-Kia EVs for nearly nine years, many looking far worse. I wrote about my own adventure (2018 Kona) in this post here years ago, and on many of the dedicated EV forums.
It's not the oil but the absence of proper sequestration or filtering of ferrous particles resulting from normal gear wear. Your best practical option is to install a couple of kick-@$$ magnetic plugs. I think the Votex DP007 will fit. (Don't use a cheapie in case the magnet drops off!)

As for oil, I've been using a thicker viscosity (75W-80 instead of 70W) for 18 months and the car does drive quieter with no measurable loss of economy. An appropriate design viscosity is determined by maximum gear tooth meshing speed ("pitch-line velocity") so you could factor your maximum (sustained) speeds over the car's maximum design speed to determine how thick you can go. I already have a pretty good idea of both of those numbers so it seems you're free to use just about anything!

But, because the oil is also used for motor cooling you'd be best to not deviate too far.

 

[ctechbob]

But, because the oil is also used for motor cooling you'd be best to not deviate too far.

Does it require the oil to have dielectric properties or is it just cooling the casing.

 

[Thugzy]

Oil looking like that has been a 'feature' of Hyundai-Kia EVs for nearly nine years, many looking far worse. I wrote about my own adventure (2018 Kona) in this post here years ago, and on many of the dedicated EV forums.
It's not the oil but the absence of proper sequestration or filtering of ferrous particles resulting from normal gear wear. Your best practical option is to install a couple of kick-@$$ magnetic plugs. I think the Votex DP007 will fit. (Don't use a cheapie in case the magnet drops off!)

As for oil, I've been using a thicker viscosity (75W-80 instead of 70W) for 18 months and the car does drive quieter with no measurable loss of economy. An appropriate design viscosity is determined by maximum gear tooth meshing speed ("pitch-line velocity") so you could factor your maximum (sustained) speeds over the car's maximum design speed to determine how thick you can go. I already have a pretty good idea of both of those numbers so it seems you're free to use just about anything!

But, because the oil is also used for motor cooling you'd be best to not deviate too far.

Appreciate this input. i came across this youtube video of both front and rear units being disassembled. I noticed when he pulled the drain plugs the rear unit was purple hazy while the front was red clear. Apparent that the rear units take all the beating since its always in propulsion. Also i notice there are magnets in both units. Adding an earth magnet to the drain plug would definitely help.

I have yet to drain my front unit. It will be interesting to see the difference in UOA between the front and rears

 

[Kiwi_ME]

Does it require the oil to have dielectric properties or is it just cooling the casing.

Hyundai-Kia specify their ATF ("HK ATF 65 SP4M-1") for all their EVs from the Ioniq 5 onwards, all of which use oil-wetted motors in both the '400V' and '800V' architectures. I've not researched it thoroughly but not seen in forums any indication that the ATF has specific dielectric properties over a normal ATF. But very few owners are reporting oil changes to provide the opportunity for feedback. This is only the second oil change I've read about in the later EVs while on the earlier H-K models many owners do it to avoid failures.

Other EV makers use wet motors, at minimum Tesla from the Model 3 onwards, VW in the iD4 and the latest Nissans. They all specify an ATF. I think if there was an important characteristic relevant to EVs we'd have some indication by now. Wet motors have proven to be so much more reliable than dry motors (that use a coolant jacket) that it's going to be the norm for all. It's nothing new - Toyota used this idea over 2 decades ago in their Prius hybrids.

... Also i notice there are magnets in both units. Adding an earth magnet to the drain plug would definitely help.

Interesting teardown. I wasn't clear about the miles accumulated but the rear unit magnet came out pretty clean. Some of those missing particles will be in the pump inlet screen (the black plastic item) and the rest will have contributing to the oil's iron PPM level, having being broken down by circulating through bearings and gears.

 

[R_Foundation]

I have an 2023 EV6 GT and am wondering whats needed to change out the front & rear reduction fluid. Is it possible to do this is in a home garage and what is a good brand to use. Thx

 

[Kiwi_ME]

Not many have done this but there is a thread here on Ioniq forum.com.
Because it’s a pumped system you can really only do a drain and fill like a conventional automatic.
You’ll have to use the dealers ATF or find an equivalent. It’s different from the older EVs like mine that use gear oil.

 

[jghall00]

Not EGMP, but I'm about to tackle this on the 2023 Niro EV I recently purchased. It has just over 85,000 miles. I have a bottle of Maxlife ATF that lists SP-IV, but not SP4M-1. Is this safe to use or no?

 

[Kiwi_ME]

There's been some indication that the 2nd-gen Niro/Kona has the same drive unit as the Ioniq 5 rear. I've also noticed Hyundai using the "E-GMP" term for 400V models as well.

I can't answer your question with any authority but being that this is a relatively-simple 2-stage parallel-shaft gear reducer the critical parameters are viscosity and the GL4 EP additives, both of which are going to be acceptable in both oils. It's not clear if the oil-cooled motor drives any additional requirements but I really doubt it. I suspect Hyundai-Kia just specify whatever is their normally-stocked ATF.

 

[GSCJR]

Is this safe to use or no?

Yes