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Cruze Manual Transmission (M32) Issues

164K views 199 replies 66 participants last post by  Cruze CTRL 
#1 · (Edited)
I wanted to create a thread that described the known issues with this transmission and their resolution. This contains the collective knowledge and experience of the CruzeTalk forum for the past couple of years, knowledge acquired from our brothers and sisters over on the Sonic Owners' Forum, and knowledge taken from overseas where the M32 is used in many Vauxhall and Holden vehicles.

Notchy Shifting
This will develop as early as 5k miles and will worsen as it goes by. If you are reading this thinking to yourself "but my transmission is fine," then you don't know what this transmission should feel like. I thought mine was fine until the problem was explained to me. If you have to force your shifter into gear as you accelerate with even a moderate amount of power, you have a problem. I'm talking up-shifting, not down-shifting. I can shift my Cruze up with a pinky. The cause of this is degraded transmission fluid.

1-2 Shift Grind
This is the result of the design of the synchros, a high 1-2 gear ratio change, and the stupid thin OE fluid shearing down too easily. The gear is fine, and the issue is mostly harmless, but it is rather annoying. Since it is synchro related, you will notice it more on the Cruze Eco than on other models, as the Eco has a higher 1-2 shift ratio change. There is no known mechanical fix. However, keep reading.

Heat
We have learned from our cousins with Holdens and Vauxhalls overseas that this transmission reaches dangerous operating temperatures with only 20 minutes of in-town driving. It is a very compact transmission and the heat has nowhere to go. A high engine operating temperature contributes to this problem.

5-6 Shaft Lubrication
Filled to the GM recommended level, the transmission starves the 5-6 gear shaft of proper lubrication. This was discovered on the Vauxhall forums when they were losing shaft bearings left and right. The solution was to overfill the transmission by half a quart, for a total of 2.5 quarts.

Fluid, the solution...sort of.

From the factory, the transmission uses a rather thin fluid, chosen for fuel economy purposes. However, it does not lubricate well (see 1-2 shift grind & notchy shifting), and it does not hold well up to heat. The solution to the notchy shifting is new fluid. Our members have used Royal Purple and Redline's offerings, and none of them perform as well as Amsoil Synchromesh. In fact, Royal Purple was the worst fluid we have tried, and the fluid ended up coming out dark and burnt.

This will sound like a sales pitch, but know that this has been tried, tested, and verified by the Gearheads on CruzeTalk. Amsoil Synchromesh completely eliminates the notchy shifting. It has a very high quality formulation of fully synthetic base stocks, and a very good friction modified package that greatly improves the function of our synchros. While it may not completely eliminate the 1-2 shift grind, it does help, A LOT. The 75W-90 GL-4 fluid has been reported to completely cure the 1-2 shift grind for many people. On my Cruze ECO, I have not yet been able to make it grind. Those who can note that even under hard driving, it happens rather rarely, in the range of 2 times a month as opposed to several times a week. Filling to 2.5 quarts total also helps with the heat issue, and provides better lubrication of the 5-6 gear shaft. EDIT: GM has officially updated the transmission fill specification to 2.32 quarts as of at least 05/2016!

Here is the fluid recommended as an OE replacement: AMSOIL Manual Synchromesh Transmission Fluid 5W-30

For tuned vehicles and vehicles driven more spiritedly, I recommend the 75W-90 transmission fluid and transaxle gear lube: AMSOIL Manual Transmission & Transaxle Gear Lube 75W-90



Disclaimer: These products aren't officially recommended by AMSOIL's technical team due to variations in specification (and the constantly changing OE specification). Use at your own discretion, as I cannot be held liable for any side effects or problems. This product is offered as an option based on the success others have had with it.

More information on Gen1 Cruze Clutch and Shifting upgrades: https://www.cruzetalk.com/forum/10-gen1-powertrain/236181-gen1-cruze-clutch-shifting-upgrades.html
 
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#2 ·
Order placed.
Going with 3 quarts for a 2 1/2 qt fill. I only have 2500 miles on it. And want the good stuff in it to help prevent issues down the road. Did an oil change today to get the break in oil and shavings out. Went with Pennzoil Platinum (on sale at local Advanced auto for 24 bucks with filter). I plan on changing it out in another 2500 miles to ensure all the break in oil and shavings are out. From there I will either go with Pennzoil Ultra or Amsoil.
Do i need to change this oil out in ONLY 2500 miles? Who cares.... its my money and my engine. Going on a road trip to VA soon, with 9 hours each way, all highway miles with light city driving while Im there. Shoild be good enough to flush out the engine before I drop money on a more expensive oil.
 
#4 ·
Yeah I know I could go more, but I want Pennzoil Ultra or Amsoil in there. The only Penn Ultra they had at3the time was euro 10w 40. "Back in the day" I was a diehard Mobile 1 fan...... times change, as well as the formula. When I had my 99 Trans AM I would change the synthetic oil no less than every 3000 to 3500k miles. She was ran a little hard. But fun to drive.
 
#5 ·
How does the current Mobile 1 do? My dealership also has Mobile 1 oil they will use instead of the AC Delco oil.
 
#6 ·
Not very good. It's not a true synthetic anymore. Just a group 3 hydrocracked oil. Amsoil and Pennzoil are one of the only ones left that make a true PAO/Ester synthetic oil. I have a thread in the 1.4T section on it.

Sent from mobile.
 
#9 ·
I'm glad I came across this post. My manual 6 speed in my ECO started grinding 3rd gear at about 60k miles. It usually only did it under acceleration. I now have 84K miles on it and have finally taken it in. The next day the dealer called me and told me that they were ordering a new transmission for it. Thankfully its covered under their 100k mile drive-train warranty. I'm thinking of putting 5k miles on the new tranny to work out all the break in trash then switch over to Amsoil. Has anyone had to get a new transmission because of grinding gear issues?
 
#11 ·
Service interval for that transmission was update for the 2014 owner's manual to 45k miles per fluid change. You exceeded that by almost double. The notchy shifting should have given it away. Now you know just how poorly GM chose their fluids for this transmission.

500 miles tops before you get a better fluid in there.

Sent from AutoGuide.com App
 
#12 ·
We have a few reports of manual transmissions being replaced due to gear issues.
 
#15 ·
OK, an update on my tranny issue. The dealership just installed a new transmission in my Cruze and the reason for the replacement was......

removed trans open side cover and found third gear syncro and blocker ring coming apart found parts are not available not service ordered new trans installed.

This is how my paperwork read. Cars runs great now. Next step is to get my AMSOIL in.
 
#16 ·
Hello Gunrunr,

Thank you for the update! I'm happy to hear that the car is running well for you, and you are back to enjoying your Cruze. If there is anymore assistance needed or if you have any questions, please don't hesitate to reach out to us.

Patsy G
Chevrolet Customer Care
 
#21 ·
Got a question for anyone with the 13+ M32 trans. Does your shifter have a lot of side to side slop when in gear?

If I'm in gear I can wiggle the shifter side to side like 1". 1st. 2nd, 5th, 6th have the most play and 3rd, 4th have just a little. I highly doubt this is normal but since the my trans was replaced with the updated version (with different style linkage) I'm not positive.

Here's a pic of the shifter linkage for the updated trans, the older style looks a good bit different. If yours looks like this please let me know how much play you have in the shifter while in gear.

 
#22 ·
I'm guessing that this may be the issue I've been having with my '12 cruze LT? It's started grinding moving from 1st to 2nd and 2nd to 3rd gear the past couple of weeks and it has been notchy since, well pretty much the day I got it? I just figured that was the way they made it to shift. my question is, with it grinding has something already gone wrong? Will replacing the fluid help at this point, or am i looking at running into the same thing Gunrunr did, and looking at having to drop a new tranny in it with the grinding gears issue?
 
#23 ·
The grinding is caused by the fluid not being thick enough to allow the synchros to engage properly, and the notchyness is caused by the same. The fluid will resolve the notchy problems and either greatly aleviate the grind or cure it altogether.
 
#24 ·
I put the Amsoil in my eco manual 15,000 miles ago, after having put 6000 on the car with the original fluid. It is a 2014. This oil made a huge difference. Runs like a top.


However, how many miles can I run it like this before replacing it? 100,000? 50,000? (I also overfilled it to 2.5 quarts.)

Finally, if you could provide any links to articles focused on this unique manual transmission, I would appreciate it.
 
#25 ·
There aren't a whole lot of articles around. Most of it can be found by going to google.co.uk and searching for "m32 gearbox."

Glad you swapped it in and noticed a difference. Pretty much everyone does. You should be good for 40-50k on this fluid before shifting starts becoming inconsistent.
 
#32 ·
When the engine is cold, my MT have some difficulty to shift into 2nd gear, it's not grinding, but you feel that there is a little resistance. Do you think the amsoil would resolve the problem? Do you have a how to for changing the trans. oil?

Thank you!
 
#38 ·
AMSOIL doesn't provide a "matching" fluid for the ECO MT. I'm running AMSOIL syncrhomesh. They have a second fluid that works for colder climates as well.

Strange that the 2013 cruze owners manual shows automatic transmission change interval but nothing for the manual.
Download the 2014 Owners Manual and use the Severe service schedule with two modifications. Clutch/Brake fluid every 30,000 miles and Syncrhomesh every 45K miles. The OE synchromesh is really only good for 15K miles and even then it's a little too thin for the 1->2 shift under load.
 
#42 ·
Okay, so questions, I drive with spirit more often than not, so I'd use the 75w90 setup, yes, but I think I've read something that saidthe 75 is not going to improve shifts quite as much. Is this true?

Second, I went and bought some Lucas 75-90 and it has limited slip additives, that's a no no, correct?

Just asking beforeI did the switch. .
 
#47 · (Edited)
Haha glad I checked. I'm an auto tech, but not fluid proficient. I fix stuff and build for power and trust others for fluid recommendations.

It is a gl4/5 deal, says full synthetic. Honestly, was getting some stuff for the Harley and some headlight bulbs for my car and as I walked past remembered this topic and decided to grab something. Brought it home and was looking at it and decided to check here before returning, friction modifier on the bottle was enough to make me weary.


As far as that display in the stores, that's of their additive, in engine oil it hides problems, and we'll but it also nearly doubles the thickness of the oil. I, personally, don't add anything to oil ever, I'll pull an engine and rebuild before that.
 
#48 ·
Yeah by the time you add something to make your own special blend, you could have gotten a better oil to begin with. If you paid $700 with tax title tags out the door for something, then yeah. Your intent was to get by on short trips for the winter or as a parts fetcher until the engine build was complete and dropped back into your real car.
 
#51 ·
After that, follow the GM recommendation of 45k miles under severe service driving. You could probably double that if you do 100% light highway driving.

The Synchromesh fluid is good for 45k miles but this being thicker should be fine for a tad longer than that.
 
#56 ·
Just wanted to throw in my 20mi experience since I swapped to amsoil today then drove home from work with it.

Shift feel? Still kinda "gear feeling" but much more positive. Drove light and heavy and couldn't get it to replicate the random half shifts I'd been getting where it seems to almost pop back out.

Shifts in heavy driving didn't just glide in like I had hoped, but you can be authoritative without it grinding like before.

Overall I'm happy. Maybe it will get smoother, but if it doesn't, its cool. I can feel a difference that feels like a healthier unit and frankly, mechanical feels in a car get my gears all Spinny anyways.

Next mods will include short shifter, which I'm slightly intimidated by because of the lack of tutorial for the newer boxes, and a tune.

Just thought I'd share my experience with everyone.

Gerald
 
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