MG4 Reduction Gearbox Oil Leak

Leni16 said:
Agree completely but it is the great unknown, the long term impact if the box is being run with less, it could be fine, it could impact it in other ways, stopping short of failure. Nobody knows.

I think the only thing that could be said is if it's true the levels have been dropped that MG are taking a gamble.
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Much more likely that they've determined a lower level is absolutely fine, especially when they have told us exactly this: they consulted with the manufacturer about the level. There's a wide engineering tolerance with these kinds of things, it can probably work fine with half the oil in it.

It makes no sense that they would "risk it" when they are on the hook for the warranty for years.

Leni16 said:
What is different about the MG 4 that causes it to leak???
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It is obviously not the same gearbox and not the same ratio, could well come from the same family but not be identical. There will probably have been several engineering revisions during the first few months of production once the leak manifested.
 
tsedge said:
It is obviously not the same gearbox and not the same ratio, could well come from the same family but not be identical. There will probably have been several engineering revisions during the first few months of production once the leak manifested.
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You could be right there tsedge but it quite strange that all three full EV drive trains use the same type and amount.
As for revisions that to is possible and this is where the baffle plate written about many times might have been forgotten anything is possible but I think unlikely.

I’m more of the line of a redesign because the drive unit now has been fitted at the rear and the breather assembly is different due to the lack of headroom can’t wait for a picture of the 5 unit.
Les
 
tsedge said:
Much more likely that they've determined a lower level is absolutely fine, especially when they have told us exactly this: they consulted with the manufacturer about the level. There's a wide engineering tolerance with these kinds of things, it can probably work fine with half the oil in it.

It makes no sense that they would "risk it" when they are on the hook for the warranty for years.
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Risk of the odd failure v cost of admitting failure.
I think they would be willing to risk it.
 
I do hope that there are no future gearbox issues arising from this. I do think that it’s unlikely.
If there are, I’m afraid that you can be sure that MG will do their best to avoid them and pay as little as possible. Their reputation is somewhat tarnished in this area.
 
Cocijo said:
I do hope that there are no future gearbox issues arising from this. I do think that it’s unlikely.
If there are, I’m afraid that you can be sure that MG will do their best to avoid them and pay as little as possible. Their reputation is somewhat tarnished in this area.
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When you see the hoops people are having to jump through with issues, with cars that are only a few months old, we can only imagine what it will be like in 3,4,5 years time.
 
Leni16 said:
When you see the hoops people are having to jump through with issues, with cars that are only a few months old, we can only imagine what it will be like in 3,4,5 years time.
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Indeed. I'd rather take simple, dirt cheap preventative measures than hope I can rely on the muppets at MG to do the right thing if the :poop: hits the fan.

'A whine from your transmission at 54,000 miles sir ? totally normal wear and tear, have a nice day'
 
MG5 EV gearbox (Roewe Ei5 actually, the Chinese market MG5 EV)
From a second hand website.
image_editor_1680722624996.jpgimage_editor_1680722607723.jpgimage_editor_1680722594111.jpgimage_editor_1680722585772.jpgimage_editor_1680722570272.jpgimage_editor_1680722526831.jpg
Here is another second hand Roewe Ei5
Including motor, gearbox and control unit.
image_editor_1680722979586.jpgimage_editor_1680722992602.jpgimage_editor_1680723002596.jpgimage_editor_1680723012396.jpgimage_editor_1680723020404.jpgimage_editor_1680723031127.jpgimage_editor_1680723051097.jpg
someone claims this is the complete unit from MG4 (MG Mulan)
Including motor, gearbox and control unit.
image_editor_1680723723070.jpg
I believe this is the one actually for MG4, the above one could be the same unit but front mounted version (another SAIC car used same motor at front axle)
image_editor_1680724803858.jpg
Front axle mounted version, same motor as MG4.
Not sure whether the gerabox is the same or not. The control unit should be the same due to the same motor.
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Interesting... thanks for that. Does look very familiar, only the drain plug being on the other side of the casing being obvious to me.
Note that there is an oil shield protecting the breather outlet in the exact same spot as the 4's unit.
Surely the 4 has the same casting... or does it. The mystery deepens....
 
Macadoodle said:
Interesting... thanks for that. Does look very familiar, only the drain plug being on the other side of the casing being obvious to me.
Note that there is an oil shield protecting the breather outlet in the exact same spot as the 4's unit.
Surely the 4 has the same casting... or does it. The mystery deepens....
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Perhaps the first batch didn't for some reason and the 2023 ones do.
 
It would be a truly bizarre thing to omit, why would they expect anything other than trouble by doing so ?
I'm going to investigate next time I'm under there though, should be an easy enough thing to feel with a screwdriver now we know what we're looking for.

Edit- Notice how the shield is shaped on its right side so it dribbles the oil wash it will receive from the big ring gear down to lubricate the motor output cog.
That cog will be spinning at maybe 10,000 rpm at a fast cruise, and it's located really close to the breather. Would be my main suspect and might explain why me moving the breather to a spot on the other end ( and on the side ) of the box cured the problem.
 
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Macadoodle said:
It would be a truly bizarre thing to omit, why would they expect anything other than trouble by doing so ?
I'm going to investigate next time I'm under there though, should be an easy enough thing to feel with a screwdriver now we know what we're looking for.
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let me know if you need more photo.
I can try ask the seller to take more photos.
 
Has this issue finally died down a little? I’m hoping that fewer owners are now reporting oil leaks and those that have had leaks has been rectified? Or is it still rumbling on as bad as ever? I would hope that latest car deliveries don’t now have leaks?
 
Cocijo said:
Has this issue finally died down a little? I’m hoping that fewer owners are now reporting oil leaks and those that have had leaks has been rectified? Or is it still rumbling on as bad as ever? I would hope that latest car deliveries don’t now have leaks?
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My car went in this morning for many bits. Last time it was in, the modified breather was "misting" so we will see what happens today. Tech Manager told me new vehicles are coming with a new breather different to the modified one fitted to my car. It seems I have modified breather Mk1 and new cars being fitted at the factory with MK2 (longer breather). Interestingly, for existing cars with leak, MG are sending the Mk1 breather as a fix still as of today, not the Mk2 that is being fitted to new build cars.
 
Crawfyp said:
My car went in this morning for many bits. Last time it was in, the modified breather was "misting" so we will see what happens today. Tech Manager told me new vehicles are coming with a new breather different to the modified one fitted to my car. It seems I have modified breather Mk1 and new cars being fitted at the factory with MK2 (longer breather). Interestingly, for existing cars with leak, MG are sending the Mk1 breather as a fix still as of today, not the Mk2 that is being fitted to new build cars.
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Interesting - Peeps have posted that they have had this part fitted - Which is the MK2 version >?< Or have I missed something ?
 

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JuziWomble said:
Interesting - Peeps have posted that they have had this part fitted - Which is the MK2 version >?< Or have I missed something ?
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That looks like the Mk1 version which is fitted to my car and the one MG are sending out for existing cars with oil leak when dealers report the fault. I was told this morning that new cars are being shipped with a "Mk2" breather which is longer than the one in your picture.
 
I was told that that was the MK2 modified breather (and that's what was fitted to my car last week) ... the MK1 modified breather looked similar but reused the old black "top hat" as far as I recall.
 
The one in the picture above is the one fitted to my car and there is a newer, longer one which is being fitted at the factory only so I was told by Tech Manager. He showed me a pile of breathers on his desk in plastic bags which were for existing cars and that was the same as mine. He then said new cars now come with a different one 🤷‍♂️ - his point was, why are they not sending the latest when the fault is logged.
 
siteguru said:
I was told that that was the MK2 modified breather (and that's what was fitted to my car last week) ... the MK1 modified breather looked similar but reused the old black "top hat" as far as I recall.
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They look almost identical, so not sure what the difference is unless as I suspect that the mark 2 may not contain a ball valve, which would eliminate pressure build up and spitting effect.
 

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