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Car has ~ 35,000 miles; did annual oil and filter change as well as first ATF fluid drain and refill.

The ATF fluid change did wonders to alleviate what I call my 2 step EV take off mode. This is where when you launch from a stop with low to moderate acceleration, you will feel a slight "bump". I believe this is when the car switches from Motor A (smaller) to Motor B (larger) via clutches in the planetary gear set. The phenomenon is non consistent, depends on fluid temperature, and pedal demand. But it's definitely there. With the ATF fluid change, it's totally gone.

The torque transfer from the electric motor (in EV mode) through the planetary gear set and clutches seems more immediate, whereas before with the older ATF fluid, there is a slight rubber band effect. Makes the car a little more sprightly now.

Lastly, while I do not have severe "chuggle", I did feel sometimes the effect of the clutching in and out between planetary gearsets with the old ATF fluid, it's much smoother now when transitioning between the 3 different modes in CS (engine on) mode.

I highly encourage changing ATF fluid if you having either of these 2 symptoms. Drain and fill of ATF fluid (for my case) is 5 QT. Drain plug on transmission is accessible after removing driver's side aero shield.

FWIW I'm using Amsoil Signature Series ATF and engine oil (5W-20) with AC Delco PF64 oil filter.
 

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Gen 2 I assume?
Amsoil makes very good synthetic products....been using them for years on all of my automotive and marine products.
 

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Don't see how changing ATF at that age would affect it but low ATF would and an oil change would fix it. Are you sure the ATF wasn't low to begin with?
 

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If he consistently drives it hard like a normal car and doesn't hypermile like most here seem to then its absolutely feasible. The pressure additives and friction modifiers in ATF breakdown (yes even at 30k miles) so replacing the fluid renews the friction modifiers and can alleviate internal clutch issues.
 

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Just as a side note, effective 4/27/18 only #19353429 trans fluid is approved for the Gen 2 Volt, the Bolt, Spark EV and CT6 Plug-in. Originally, Dexron VI was the fluid approved for the drive, but GM changed that to the above number.
 

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Changing the transmission fluid is a great idea, especially if you plan on keeping your Volt for the long term. You'd be surprised what a couple electric motors and clutches submerged in ATF fluid can do to contaminate and break down the fluid. The high mileage Prius guys figured this out quite a while ago.
 

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Where is the danf
Car has ~ 35,000 miles; did annual oil and filter change as well as first ATF fluid drain and refill.

The ATF fluid change did wonders to alleviate what I call my 2 step EV take off mode. This is where when you launch from a stop with low to moderate acceleration, you will feel a slight "bump". I believe this is when the car switches from Motor A (smaller) to Motor B (larger) via clutches in the planetary gear set. The phenomenon is non consistent, depends on fluid temperature, and pedal demand. But it's definitely there. With the ATF fluid change, it's totally gone.

The torque transfer from the electric motor (in EV mode) through the planetary gear set and clutches seems more immediate, whereas before with the older ATF fluid, there is a slight rubber band effect. Makes the car a little more sprightly now.

Lastly, while I do not have severe "chuggle", I did feel sometimes the effect of the clutching in and out between planetary gearsets with the old ATF fluid, it's much smoother now when transitioning between the 3 different modes in CS (engine on) mode.

I highly encourage changing ATF fluid if you having either of these 2 symptoms. Drain and fill of ATF fluid (for my case) is 5 QT. Drain plug on transmission is accessible after removing driver's side aero shield.

FWIW I'm using Amsoil Signature Series ATF and engine oil (5W-20) with AC Delco PF64 oil filter.
[/QUOTE
Car has ~ 35,000 miles; did annual oil and filter change as well as first ATF fluid drain and refill.

The ATF fluid change did wonders to alleviate what I call my 2 step EV take off mode. This is where when you launch from a stop with low to moderate acceleration, you will feel a slight "bump". I believe this is when the car switches from Motor A (smaller) to Motor B (larger) via clutches in the planetary gear set. The phenomenon is non consistent, depends on fluid temperature, and pedal demand. But it's definitely there. With the ATF fluid change, it's totally gone.

The torque transfer from the electric motor (in EV mode) through the planetary gear set and clutches seems more immediate, whereas before with the older ATF fluid, there is a slight rubber band effect. Makes the car a little more sprightly now.

Lastly, while I do not have severe "chuggle", I did feel sometimes the effect of the clutching in and out between planetary gearsets with the old ATF fluid, it's much smoother now when transitioning between the 3 different modes in CS (engine on) mode.

I highly encourage changing ATF fluid if you having either of these 2 symptoms. Drain and fill of ATF fluid (for my case) is 5 QT. Drain plug on transmission is accessible after removing driver's side aero shield.

FWIW I'm using Amsoil Signature Series ATF and engine oil (5W-20) with AC Delco PF64 oil filter.
Where is the dang drain plug on the trans axle??
I can't find it.
I am just going to drain the fluid and just put back however much drained out.
I will just buy the fulid from the dealer, I paranoid about messing with transaxle.
Done.
 

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CeeW,

There is a post on that:


Stephen
 

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CeeW,

There is a post on that:


Stephen
I've seen that one, but I guess there is no drain plug?
Just a fill-level hole for the trans?
 

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Nice!
Finally! This is what I have been looking for with no success.
You can download the service manual?! Sweet!
I will try to find it.
 

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Welp, I can't find a service manual to download......I thought I knew how to use the internet! arg!
Where can I find it??
 

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Don't see how changing ATF at that age would affect it but low ATF would and an oil change would fix it. Are you sure the ATF wasn't low to begin with?
GM is known for underfilling the ATF fluid at the factory on other cars so I can see them doing this with the Volt.
 
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