Hi all, I just entered the 73k mile mark and can’t stop thinking about the transmission fluid. As far as I am concerned, there is no such thing as “lifetime” fluid and was wondering if anyone has changed their transmission fluid? Thank you in advance. Oh and btw, current gas prices in CA are $4 a gallon, super happy with the bolt.
Transmission Fluid
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Omar
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Possibly will, though I've got another 20,000 miles before I plan to do it at least. The Weber video I posted above talks about performing it if you're curious in the meantime.
If you ever get around to doing that. can you post a quick DIY?Yep! It's all covered. I never want to have an issue and feel changing it after break-in is a beneficial service. At least the one time service will make my long term ownership feel less worrisome.
Lifetime fluids just make no sense to me. A fluid change is a very minimal maintenance item.
When I do this, I'll post an image of the material that comes out and into the drain pan.
I've seen it before. I've done it before. My final drive was full of metal to the point of turning silver.
I can't find the pictures so you can see for yourself. We shall see what the Bolt looks like
I plan to run mine past the warranty, so why not take care if it. If you don't care about it
after the warranty period, that great for you. I have long term plans for this car. YMMV!
Thanks.
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238 Posts
I am somewhat interested in the topic and want to ask the contributors some questions for consistency.
If I pick some of the mileage figures given for transmission fluid change in a 'lubed-for-life' system, say 60,000 miles, there seems to be the belief that after so many cycles or time there will be a degradation of the fluid that can be mitigated by changing it.
So, at 60,000 miles and at 815 revolutions to the mile for the stock tires, the output gear of the transmission has rotated 48.9 million revolutions.
Some other questions for consistency
If I pick some of the mileage figures given for transmission fluid change in a 'lubed-for-life' system, say 60,000 miles, there seems to be the belief that after so many cycles or time there will be a degradation of the fluid that can be mitigated by changing it.
So, at 60,000 miles and at 815 revolutions to the mile for the stock tires, the output gear of the transmission has rotated 48.9 million revolutions.
- Why are there no comments or desires to change the wheel bearing hubs? After all, these also have seen 48.9 million revolutions, plus radial impact loads from potholes and curbs. These are also lubed for life. Why not change these?
- On the other side of the output shaft, the motor turns 7.05 times as much on sealed bearings not in an oil bath. That's 344.7 million revolutions. Why aren't members of the forum replacing the motor bearings to achieve a long service life?
Some other questions for consistency
- The Bolt EV is designed for efficiency. High-efficiency EV transmissions use in-line helical gears to achieve 95-98% transmission efficiencies. This means special metal treatments and polished, matching gear surfaces. It also means reducing the number of pairs of gears. Why would you expect to see metal shavings in the fluid? Why compare these transmissions to motorcycle transmissions?
- The Bolt EV uses a continuous circulating transmission fluid pump driving the fluid through a non-serviceable filter (Weber Auto). Wouldn't the filter permanently trap any debris? What do you expect to see?
- The Bolt EV transmission specifies Dexron HP as the transmission fluid. Dexron HP contains oxygen and water scavengers. It is filled under clean, controlled conditions. After a short period in a sealed case, the fluid is essentially working in a hermetically sealed, dry nitrogen atmosphere. Can you complete a driveway drain and fill, with the associated fill protocol, without contamination?
Gear oil change
This is a great question. I've called my dealer, I've called another dealer, And I've contacted Chevrolet customer care with this question. Not one person at the company knows the answer to this question. I've requested they escalate the concern up, and Chevy will not do this. I truly believe that if they get enough kick back from their customers, they will finally amend the Owners manual to depict when this oil needs to be changed. No Oil lasts forever, and it does need to be changed at some point and Chevy is fighting so hard to not disclose this info.
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I'm of the opinion the Bolt's transmission is similar to a rear wheel drive rear differential, which 90% (I'm not looking up the actual number but its definitely the majority) of them out there go the life of the vehicle without service or failure. Hundreds of thousands of miles. Unless you find a way to severely overheat the fluid, or a seal fails and it starts leaking out, its going to last decades.
I just checked the service manual for my '69 Firebird, it states on page 4B-3, "No periodic lubricant change is recommended." So this is not a new thing on maintenance. Only reason engine oil is changed is because the combustion gases getting by the rings contaminating and degrading the oil.
That being said. I can see me replacing the fluid around 8-10 years just because.
I just checked the service manual for my '69 Firebird, it states on page 4B-3, "No periodic lubricant change is recommended." So this is not a new thing on maintenance. Only reason engine oil is changed is because the combustion gases getting by the rings contaminating and degrading the oil.
That being said. I can see me replacing the fluid around 8-10 years just because.
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Yeah I'm going to side with the crapola. I have another older vehicle that made that claim. With this ones longer history than the Bolts, its well known to be BS. Metal gears meshing together eventually degrades a lubricant, no matter the temperature or contaminants. It probably lasts a lot longer.. but not forever. My educated seat of the pants guesstomater agrees with cataract's mile recommendation.
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Yeah, I'll be casually watching this thread.
I mean obviously as mentioned, Lifetime != forever.
But how long will it last? I own my Bolt and put about 25k on it per year.
I expect to go well over 100k while I own this car.
I don't expect to have it till 200k.
Hoping that if it does look like it needs it, we'll know.
I think NewsColoumb is near 100k on his Bolt. Maybe we'll see a vid from him on it!
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Instead of engaging in endless debate about the transmission oil, why doesn't someone just do it and report on the procedure, how hard it is to do, and what the fluid looked like. Jeeez
My 2019’s drivetrain is noisier than my 2017 (especially at lower RPMs) so I’m going to ask the dealer to drain the transmission fluid to see if there are metal shavings and/or another indication of premature wear. It will be done around 1000 miles so maybe there will be something interesting to share back with this thread. Stay tuned.
P.S. The service manual states that after the initial drain/fill, a scan tool must be used to command the transmission fluid pump to speed to ON for 1 minute for circulation. I’m assuming no one here has access to that, nor do I know if there are other ways to power on the pump (or even if that’s necessary). Just something for you DIYers to think about.
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I want to open by clarifying a piece of terminology. "Lifetime" anything refers to the service life, which typically aligns with the Warranty period. I personally prefer my equipment to last well beyond the warranty period. In some cases this is done in good faith, other times, less so. Prime example is in Zero Turn mowers. Lower end residential mowers have sealed "Lifetime" hydrostatic transmissions. In many cases the housings for the transmissions have spots marked for drain/fill points for fluid, but those are only drilled/tapped on higher end models. Same guts, just paying a premium for being able to service it as it extends life and allows it to survive under a harsher workload.
Now I'll address a couple of your questions:
- Why are there no comments or desires to change the wheel bearing hubs? After all, these also have seen 48.9 million revolutions, plus radial impact loads from potholes and curbs. These are also lubed for life. Why not change these?
- These aren't change preemptively because wheel bearings don't suffer catastrophic failures that cost a fortune to fix. (as long as you're monitoring them at least). Start hearing excess noise and notice some play? change the bearing as needed. Cost/Benefit of pre-emptive changing doesn't exist.
- On the other side of the output shaft, the motor turns 7.05 times as much on sealed bearings not in an oil bath. That's 344.7 million revolutions. Why aren't members of the forum replacing the motor bearings to achieve a long service life?
- Again, cost benefit analysis. Time, Labor, and special tools required to tear down to that level put it on a very different field vs. a fluid swap. Here's a good video walking through at least a partial teardown of the Bolt EV traction motor.
- Again, cost benefit analysis. Time, Labor, and special tools required to tear down to that level put it on a very different field vs. a fluid swap. Here's a good video walking through at least a partial teardown of the Bolt EV traction motor.
All that said, looking at the design of the motor and the fluids used. IF I bother with this at all, it'll be at either 100 or 150k miles. Then it'll depend a lot on how the rest of the car is holding up. If lots of things are falling apart at that point, then obviously it's not worth it investing time and effort into preventive maintenance that likely won't provide any benefit unless going well over 200,000 miles.
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I agree that repacking wheel bearings used to be a standard task. However on an ice car you usually notice it on brake work. Not sure my brakes will ever need replacing using mostly regen. This transmission could be quite expensive if one has to replace it because of bad oil. I'd think that the seals going would be first then other issues.
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Old saying, "Don't fix it if it ain't broke."
Just adding to this that the motor bearings aren't sealed, and they are bathed in oil by the transmission pump.
So I looked at the service manual and the procedure doesn’t look all that difficult. In a nutshell:
Drain via the drain holes (there are two spots), fill via fill or possibly the check hole, and perform final checks via the fluid check hole. Make sure transmission is up to operating temps when checking fluid levels.
The only tricky part I see is using a scan tool to rotate the tranny for 1 minute half way through the procedure. I’m assuming we can simply drive the car to achieve the same outcome.
Obviously there are more detailed steps and caveats to follow, but it seems very similar to conventional cars. The question is - is anyone on the forum past their warranty and willing to try this?
Sent from my iPad using Tapatalk
Drain via the drain holes (there are two spots), fill via fill or possibly the check hole, and perform final checks via the fluid check hole. Make sure transmission is up to operating temps when checking fluid levels.
The only tricky part I see is using a scan tool to rotate the tranny for 1 minute half way through the procedure. I’m assuming we can simply drive the car to achieve the same outcome.
Obviously there are more detailed steps and caveats to follow, but it seems very similar to conventional cars. The question is - is anyone on the forum past their warranty and willing to try this?
Sent from my iPad using Tapatalk
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40 Posts
I found this discussion interesting. I have a Kona Electric which has a similar but far more primitive gear reduction unit. I'm also a degreed mechanical engineer with industrial experience in gearboxes and power transmission design and troubleshooting, and I'm pretty fussy about keeping my vehicles maintained. On a whim I changed the gear oil last week at a mere 19,000 km, picture posted below. The Kona gearbox is purely a splash-lubricated design and puzzlingly (EDIT June 2022) does not have a the internal magnet installed is insufficiently strong enough to pick up ferrous debris, the only only type of debris you'd expect to see when all moving parts are made of steel. The reason I believe the oil is discoloured as you see is purely because that magnet is missing ineffective. The blackness is the result of ferrous particles being ground all the way down to dust. Have any Kona gearboxes failed? Yes, dozens of warranty replacements have been reported on forums. Mine hasn't, but must have suffered far more wear than it should have.
GM have provided a large magnet in the Bolt gearbox which will be good for a lifetime of collecting ferrous debris. The plastic screen under the motor is really intended to keep the big pieces out of the oil pump and should never need changing. GM's engineers have arranged the motor and pinion gear bearings correctly to avoid physical overconstraint and have avoided the superfluous use of tapered rollers on the final drive with the related complexity of setting a preload in a vertically-split housing, both present in the Kona and both asking for trouble.
In short GM have done a great good job here and I believe owners have nothing to worry about, irrespective of what you decide regarding oil changes.
![Image]()
GM have provided a large magnet in the Bolt gearbox which will be good for a lifetime of collecting ferrous debris. The plastic screen under the motor is really intended to keep the big pieces out of the oil pump and should never need changing. GM's engineers have arranged the motor and pinion gear bearings correctly to avoid physical overconstraint and have avoided the superfluous use of tapered rollers on the final drive with the related complexity of setting a preload in a vertically-split housing, both present in the Kona and both asking for trouble.
In short GM have done a great good job here and I believe owners have nothing to worry about, irrespective of what you decide regarding oil changes.
Thanks for your comments. Nice to hear this kind of analysis from someone who seems qualified to give it, as opposed to the mere layperson speculation that I'm limited to.
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