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Old 05-23-2017, 10:23 PM   #1
mja
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Default M32 Breathers

If you find M32 breather kits or have made one, post em up:


GizFab | Vauxhall M32 Gearbox Breather Kit


EP Astra H VXR M32 Gearbox Breather Kit | Enhance Performance


M32 Gearbox ? WG Motorworks
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Old 05-23-2017, 11:06 PM   #2
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I'm sorry, what's the point of breathers? I see those things on all sorts of stuff from 5.0 foxes to riced out Hondas. I always assumed they were just for looks

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Old 05-24-2017, 12:24 AM   #3
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The 6 speeds in these cars get really hot. When the oil heats up, it basically burns and changes viscosity, not offering the same protection as before.

6 speed owners can affirm this, a few hard shifts and the trans just doesnt want to shift right until cooling off, sometimes overnight. Then it shifts like butter, its a random occurence and sucks (even after readjusting the shifter cables, it still doesnt shift sometimes until cooled)

What the breather wont do is fix the problems with the trans building heat. A quality breather will allow some heat to escape the oil, retaining its lubrication qualities until the oil is changed. Ideally it wouldn't let air particles or water condensation in, or oil spray out. Just remove heat.

Problem with some of the cheap styles are the filters may allow a lot of water in. It's hard to trap water like this without a salt or dessicant filter, but good baffling helps. Some of them come with closed caps and they're simply to increase the volume of oil in the box, which is supposed to help, not sure about that. The M32 is one trans that needs a way to efficiently remove heat if tracking it or hard shifting. Honda trans are pretty stout as is, never had an issue with those.
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Old 05-24-2017, 02:14 AM   #4
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I had no idea that the Sonic, with its meager horsepower/torque output, could cause an excessive amount of heat within its manual transmission; that the proper lubricant couldn't compensate for. In this application, I believe a high performance breather is more show than go!
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Old 05-24-2017, 05:57 PM   #5
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There are plenty of owners on the forums at stock power level who can't shift their M32's at certain times, the issue is the transmission not the motor and its power level. It's why GM redesigned the front cover for motors of lower or the same power level in the US & Europe around 2011/2012.

Packing 6 gears in this tiny thing is fine. The trans doesn't care how much power is going through it if the bearings heat up and the shift fork locks from excessive heat.
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Old 05-24-2017, 10:18 PM   #6
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Quote:
Originally Posted by mja View Post
The trans doesn't care how much power is going through it if the bearings heat up and the shift fork locks from excessive heat.
That's interesting...

I've had the odd impression for awhile now that my car will shift smoother after a weekend sitting undisturbed or on a cold and rainy day than at the end of a week of spirited driving with the car 'warmed up' in the sun. I always thought I was just being super picky and imagining things.

Now you're making me question reality.
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Old 05-24-2017, 11:40 PM   #7
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Looks like a perfect example for a mod to ba made... some fab company might have a lil niche to fill... just sayin

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Old 05-24-2017, 11:59 PM   #8
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M32 history, from calling around European shops and checking out Vauxhall/Opel forums.

Unfortunately these transmissions arent common pre 2010 in the US. They've been used in Europe for a while on a few dozen different cars, their limits have been tested and are known.

When GM produced them for the US & world market in 2010, they got a new bearing contract (2010-2012) moved away from Timken to other brands which proved to be less durable. They also added the dual mass flywheel to prevent driveline shock from hard shifts, a way to manage torque... a nice unintended result of the dual mass flywheel is it dampens vibrations and lowers gearbox chatter in neutral. There are more problems with the 2012 Sonic 6 speeds than later years. They redesigned the case cover in 2011 so all Sonics should have the newer style which supplies oil more efficiently to the case bearings, but the bearings are less robust until 2013, the same year the shift tower was redesigned for more precise adjustment of the cables.

According to WG Motorworks, one of the leading aftermarket M32 rebuilders, reasons for failure are:
"poor gearbox design; oil temperatures which can exceed 115 degrees C, and failure to change the gearbox oil according to the service schedule."

Since the US M32's do not have an oil service schedule, and it is known the oil gets too hot even in stock applications 115-135 C (240-275 F), above the recommended operating temps of 75w90 or SAE50, it makes sense that so many people have shifting issues. Any ways that cool the trans or gear oil more efficiently will help, if they do more good than harm. Or we can do what the dealer does and throw away the old trans and buy a new one.
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Old 05-25-2017, 01:18 AM   #9
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Couldn't I just go full JDM instead with a massive front-mount oil cooler?
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Old 05-25-2017, 01:52 AM   #10
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Mja, i was reading the exact same info from the euro shops for Vauxhall and opels with the M32... very informative reading through it all.

I also saw the casing redesign with new oil gally and larger bearing carrier.. i have the 2012 6m32 but fortunately i have the updated casing. I was planning on changing the gear oil this summer (shes sitting at 62k mi) but wasnt in a rush but im def going to do it sooner.

As a possibility over a breather you could always try a trans cooler. Hmmm
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