# Manual transmission oil



## XtremeRevolution (Jan 19, 2012)

Same transmission, so you'd use the same oil, and fill to 2.5 quarts. Let me know if you'd like some and I can get you a quote on it.


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## 17Hatch6MT (Dec 28, 2015)

Oops, in the Gen 1 forums, I saw the 'Manual Transmission & Transaxle Gear Lube 75W-90' recommended for heavy-duty users. 

However, '*Manual Synchromesh Transmission Fluid 5W-30*', was recommended for the M-32 for normal driving. I think I saw somewhere in this forum that this gave better cold drivetrain performance also. Also saw there, it said Amsoil lubes weren't specifically recommended by Amsoil for our cars. Indeed, searching on the Amsoil site brings up nothing for the manual transmission.

The Amsoil page for this lube says, 

*'Specifications*



GM 9985648 
GM 9986105 
GM 9985535 
Chrysler MS-9224 
Chrysler MS-9417 
*Part Numbers*


GM 12345349 or 12345577 
GM 12377916 
GM 1052931 
Chrysler 4874464 
Chrysler 4874465'


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## obermd (Mar 3, 2012)

I recommend the Amsoil Synchromesh and not the heavier duty gear lube. I know some members prefer the gear lube but I found the Synchromesh to be more than sufficient.


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## ProDigit (Aug 31, 2015)

10 or 100k miles?
The oil change interval should be around 50k miles.


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## 17Hatch6MT (Dec 28, 2015)

The owner's manual says 45,000 miles, ttbomr. I thought the Gen I owners were having early transmission trouble, due both to oem spec being an underfill in practice, and to an inadequate quality of the oem oil, and that it was recommended there to change to Amsoil as soon as possible, best within a few thousand miles. The oem fill spec has been modified so that shouldn't be a concern as long as they actually put the correct quantity in at the factory. Not sure if the quality of the oem oil is sufficient. Rather not find out it isn't, the hard way.

I must say, at 10,000 miles, it's shifting better than ever. It was pretty stiff when new. That's not to say it couldn't improve a lot. The 1-2 upshift, in particular, takes a lot of time. With the wide ratio gap, it takes a while for the engine to spin down. I don't want to hurry the shift and stress the synchros. I may want to keep it long term.

In the 2001 Sentra, changing to Amsoil Synchromesh immensely improved the shifting feel and the ability to shift it more speedily. And so, I'm hoping for a performance improvement, also. Maybe also an MPG improvement.


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## cruzestout (Oct 9, 2017)

I have a 2017 Chevy Cruze LS manual transmission. I changed out the factory transmisson fluid and put in Amsoil Synchromesh with 2.5 quarts. I did notice the clutch pedal sticking off and on during hot weather. Im sure air got into the system.. Any clue if anyone knows where the bleeding valve could be on our gens?


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## blackbird (Nov 6, 2017)

The hydraulic clutch system (master cylinder at pedal and slave cylinder in trans) is completely different from the lubricating fluid that goes into the trans. If it's a 2017 and you're under warranty take it in and have the dealer check out the clutch release mechanism.

Usually when you get air in the system you'll have a spongy clutch release that's further down in the pedal travel and/or problems with the clutch not fully releasing, which often causes grinding on gear changes. If the pedal itself is sticking then you might have a problem with the actual pedal assembly. If you release the pedal and it returns to normal position but it acts like the clutch pedal is still down (disengaged in the trans) there might be a problem with the master/slave cylinder or something else in the clutch release system like the throw-out (release) bearing.

I'd also avoid telling them that you swapped to Amsoil. While Amsoil makes some nice fluids for some applications, if the Synchromesh doesn't specifically meet GM's recommended standard and viscosity it's asking for trouble to complain about trans and clutch problems and tell a dealer you're using a non-approved fluid.


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## 17Hatch6MT (Dec 28, 2015)

The Gen I Cruze Eco model has the same manual transmission that all Gen IIs with manuals have. The Gen I LS and LT have a different manual transmission. I don't know that Amsoil Synchromesh is appropriate for it. 

And, yes, the hydraulic fluid for the clutch release mechanism is completely different. I can't imagine any interaction between the type of gear lube in the case and the clutch linkage hydraulics.


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## Slayinit (Jan 8, 2013)

I used AC Delco Friction Modified Synchromesh 10-4014 in both my (previous) '00 Sentra and my (current) '13 Accord with nothing but positive results. Are the guts of these M32 gearboxes so different that this oil has no use as a replacement? Seems odd & I can't find much on the Googles. I plan on changing out the factory oil around 10K miles or so due to some folks posting that the factory fill is pretty weak stuff. Gotta wonder if GM learned from the Gen 1 M32s and not only filled them properly but with decent oil, too. Time will tell. Gotta love the internet....mostly.

PS - I miss my older Hondas. Owners manual said (paraphrased) "Swap out the gearbox oil with some 10W-30 every 30K miles or so." So easy.


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## cruzestout (Oct 9, 2017)

Thanks for the information I should had left it alone and had not changed the fluid but since i was changing out the oil to Amsoil figured I would change the transmission fluid as well, since from hearing and reading up on the first gen's having their issues and some had impressive results from changing it knowing they use the same M32 with the fluid not so great. I assume all results are different. With me i notice the clutch pedal was sticking to the floor shortly after i changed the fluid but again it would go back to normal moment without any sticking or grinding while shifting for days... So i knew it either something is going out or maybe a leak could be forming. So i check everything over again and things are looking good so just stumped me. If I pumped up the clutch pedal with my foot did notice i had more response from the pedal and wouldn't act up for a few days of driving. So with a little more research about our transmissions i figured it out and maybe solved up my mess. only days will tell though... Worst case i still have the old oem fluid that i could put back in and have the dealership tackle with it.


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## billyu (Apr 10, 2020)

17Hatch6MT said:


> The owner's manual says 45,000 miles, ttbomr. I thought the Gen I owners were having early transmission trouble, due both to oem spec being an underfill in practice, and to an inadequate quality of the oem oil, and that it was recommended there to change to Amsoil as soon as possible, best within a few thousand miles. The oem fill spec has been modified so that shouldn't be a concern as long as they actually put the correct quantity in at the factory. Not sure if the quality of the oem oil is sufficient. Rather not find out it isn't, the hard way.
> 
> I must say, at 10,000 miles, it's shifting better than ever. It was pretty stiff when new. That's not to say it couldn't improve a lot. The 1-2 upshift, in particular, takes a lot of time. With the wide ratio gap, it takes a while for the engine to spin down. I don't want to hurry the shift and stress the synchros. I may want to keep it long term.
> 
> In the 2001 Sentra, changing to Amsoil Synchromesh immensely improved the shifting feel and the ability to shift it more speedily. And so, I'm hoping for a performance improvement, also. Maybe also an MPG improvement.


Hello - can you point me to the new oem fill spec? How much is it for the manual transmission? I just had the transmission replaced under warranty at the dealer and they are still only filling to 1.5q or so.... thanks.


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## 17Hatch6MT (Dec 28, 2015)

Recollections, not 100% sure... 2.5 US quarts for the OEM recommendation. 2 2/3 quarts going by the earlier posters' (Gen I) recommendations before the OEM updated theirs. May check later but it's not convenient at this time. 

I'm at about 18,000 miles on the OEM fill, no problems yet.


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## Barry Allen (Apr 18, 2018)

Here is a lengthy read on the M32 gearbox: 









M20 & M32 Gearbox: Chocolate Bearings - Still Running Strong


The ULTIMATE GUIDE to the infamous M32 gearbox. Learn everything about bearing failures in the M32 and M20 gearboxes - Causes, Symptoms & Repairs.




stillrunningstrong.com





It appears GM updated the transmission in 2012 to put in better bearings and to improve oil flow through the gearbox.

Instructions for changing oil in the gearbox explain that about 200ml of oil will remain in the case after a complete draining. You can add 2.5 quarts and that comes out to about 2.37 liters, which is comfortably between the recommended 2.2 and 2.6 liters of fluid refill (depends if you desire to "overfill" the gearbox a bit for added comfort that enough oil is lubricating the bearings).

Use a synthetic 75W-90 gear oil such as Amsoil or Mobil 1. This is a little bit thicker than the 75W-85 factory viscosity from GM. Mobil 1 is available at lots of auto parts stores so it might be easier to get than Amsoil. A good synthetic oil like this should last to a 40,000 or 50,000 mile change interval, depending on what you want to do.


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## Blasirl (Mar 31, 2015)

Barry Allen said:


> Use a synthetic 75W-90 gear oil such as Amsoil or Mobil 1. This is a little bit thicker than the 75W-85 factory viscosity from GM. Mobil 1 is available at lots of auto parts stores so it might be easier to get than Amsoil. A good synthetic oil like this should last to a 40,000 or 50,000 mile change interval, depending on what you want to do.


@XtremeRevolution will ship to your door.


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## XtremeRevolution (Jan 19, 2012)

Barry Allen said:


> Here is a lengthy read on the M32 gearbox:
> 
> 
> 
> ...


Small correction: OEM fluid is actually thinner than that even. I'd estimate it on the low side of the SAE-80 scale. 

Sent from my BlackBerry Key2 using Tapatalk


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## Barry Allen (Apr 18, 2018)

XtremeRevolution said:


> Small correction: OEM fluid is actually thinner than that even. I'd estimate it on the low side of the SAE-80 scale.


I have no information one way or another that there is a better gear oil to use. For all I know the GM synthetic gear oil could work just as good as Amsoil or M1. I think the important part is to ignore the general idea that it is a "lifetime" fill of the gearbox unless you intend to get rid of your car before you physically wear it out.

An oil change interval of 50,000 miles is probably a good idea for the manual gearbox, maybe even as short as 40,000 miles if you primarily drive in a hot climate.


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## Blasirl (Mar 31, 2015)

Can anyone confirm or deny that the manual trans is the same on both the gen I and Gen II? Or maybe it is close as maybe the bell housing and such is different?


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## Barry Allen (Apr 18, 2018)

Blasirl said:


> Can anyone confirm or deny that the manual trans is the same on both the gen I and Gen II? Or maybe it is close as maybe the bell housing and such is different?


It's the same transmission used on many GM products (and Fiat, and others in Europe) for over 15 years. The transmission was updated in 2012 for more reliability, so there might be Cruze sedans 2010-2012 that have an earlier version.


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## plano-doug (Jul 1, 2015)

Blasirl said:


> Can anyone confirm or deny that the manual trans is the same on both the gen I and Gen II? Or maybe it is close as maybe the bell housing and such is different?


Attached is a list I put together during one of my nerdier moments  It lists all the tranny and engine combos available from 2011-2018. It shows at least four different versions (RPO's) of the M32-6 spanning gen1 and gen2.

Besides RPO's, you might want to compare trans tag info as well, to be more sure of a match, JIC.

I culled the info from GM catalogs/brochures I got off the web.

The data format is carried over from the brochures, and it's a little different year-to-year, so any wonkiness is GM's fault. For example, in 2014, they list the LUV/M32-6(MF3) twice.

In the case of 2016, I think the last line applies to gen2's, while the 4 lines above it are for gen1/limited.

[Edit]Revised attachment, added header.

HTH.
Doug

.


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## Blasirl (Mar 31, 2015)

plano-doug said:


> Attached is a list I put together during one of my nerdier moments  It lists all the tranny and engine combos available from 2011-2018. It shows at least four different versions (RPO's) of the M32-6 spanning gen1 and gen2.
> 
> Besides RPO's, you might want to compare trans tag info as well, to be more sure of a match, JIC.
> 
> ...


Nice list. It looks like we need someone with access to a Hollander interchange manual or database to confirm. I wanted to know so when someone with different years trans asked questions, could I freely give basically the same answers. While all of the manuals are listed as M32-6's, aside from maybe mounting patterns and such, do they all use the same fluids, can the mods from Gen I's be performed on Gen II's etc.

Thanks for the list.


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## Barry Allen (Apr 18, 2018)

Blasirl said:


> While all of the manuals are listed as M32-6's, aside from maybe mounting patterns and such, do they all use the same fluids


It's all the same transmission. They all use some GM synthetic gear oil rated GL-4 as factory fill. You can replace it with the same or similar GL-4 gear oil, with the best advice being to go up a little bit with viscosity so you have better oil film strength.


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## Blasirl (Mar 31, 2015)

Well then, this is my manual trans list:

Cruze Manual Transmission (M32) Issues
How-To: Change the Manual Transmission Fluid
How-To: Install Clutch Accumulator Bypass Mod
Gen1 Cruze Clutch and Manual Transmission Shifting Upgrades
How-To: Remove Clutch Delay Valve (CDV)
How-To: Replace Clutch Fluid
AMSOIL 75W-90 GL-4 Manual Transmission Fluid
AMSOIL Products for the 2011-2015, 2016 Limited Gen1 Cruze


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## Barry Allen (Apr 18, 2018)

Blasirl said:


> AMSOIL 75W-90 GL-4 Manual Transmission Fluid


Whoops, let me edit this comment to say I _WAS_ planning on using Mobil 1 75W-90.

Just looked it up to find it's a GL-5 gear oil. I'll need to get on the Amsoil website to get a GL-4 gear oil.


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## Barry Allen (Apr 18, 2018)

plano-doug said:


> Attached is a list I put together during one of my nerdier moments  It lists all the tranny and engine combos available from 2011-2018. It shows at least four different versions (RPO's) of the M32-6 spanning gen1 and gen2.


The manual for my 2018 lists GM Part No. 19259104 for my manual transmission. Looking that part number up on shows it's a GL-4 rated "manual transmission fluid."

I'd be curious to go through the GM website and look at PDF copies of the owner's manual for each model year to see if any different oils are listed.


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## Davep (Apr 14, 2014)

I've used the AmsOil Synchromesh in my 2014 M32 since new. I live in Ontario Canada, (so a cooler climate), but the Synchromesh has performed flawlessly. (Especially during cold winter starts.) You may want something heavier in a warmer climate.


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## plano-doug (Jul 1, 2015)

Barry Allen said:


> I'd be curious to go through the GM website and look at PDF copies of the owner's manual for each model year to see if any different oils are listed.


Ask and ye shall receive 

Looks like, other than 2011, it's the same for all succeeding years, GM p/n: 19259104 (19259105 in Canada).

Doug 


Cruze year​Listed manual transmission fluid (from owner's manuals)​2011​Castrol BOT 0402 Transmission Fluid (GM Part No. 88862472, in Canada 88862473).​2012​Manual Transmission Fluid (GM Part No. 19259104, in Canada 19259105).​2013​Manual Transmission Fluid (GM Part No. 19259104, in Canada 19259105).​2014​Manual Transmission Fluid (GM Part No. 19259104, in Canada 19259105).​2015​Manual Transmission Fluid (GM Part No. 19259104, in Canada 19259105).​2016 ltd​Manual Transmission Fluid (GM Part No. 19259104, in Canada 19259105).​2016​Manual Transmission Fluid (GM Part No. 19259104, in Canada 19259105).​2017​Manual Transmission Fluid (GM Part No. 19259104, in Canada 19259105).​2018​Manual Transmission Fluid (GM Part No. 19259104, in Canada 19259105).​2019​not listed​

.


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## Barry Allen (Apr 18, 2018)

Davep said:


> You may want something heavier in a warmer climate.


Yeah, it is hot and nasty humid (which doesn't matter) here in Central Illinois. Highs sometimes approach 110 F if we get a good heat wave in July and/or August.

It's no Phoenix in terms of consistently high roasting temperatures, but I need an oil that can perform in these temperatures. In winter the gearbox might get a little stiff, but I just shift slower when I'm driving away from a cold start.


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