# Eco 6 speed manual grind



## sciphi (Aug 26, 2011)

Yep, that's how this beast is. Lots of posts on this. Changing the OEM swill for a synchromesh or 70w-80 GL-4 gear oil makes the problem from the transmission side mostly disappear. 

Driver error can still occur. Make sure the clutch is matted when doing a fast 1-2 shift. It seems the 2nd gear synchro loves to be where it shouldn't be during a high-RPM/high-load shift, and needs extra caution. 

Nowadays when I grind 2nd it's because of my error in not depressing the clutch enough, not because of the transmission.


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## XtremeRevolution (Jan 19, 2012)

Please review this thread, and contact GM Customer support as noted in the 2nd page to have them set you up with a dealer:

http://www.cruzetalk.com/forum/25-service-issues/7303-does-your-transmission-grind.html

It appears that GM is aware of the problem, and you may be able to have something resolved by following this route.


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## Skilz10179 (Mar 22, 2011)

GM is never going to do anything about it, sell your car.


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## Rockerxink820 (Aug 8, 2011)

Well I was having that problem as well but it also went from 3-4 they said it was the syncro and replaced the whole transmission. Now after about 13*** miles in the new transmission I m seeing g the problem again with my 1-2 high rpm shift it grinds so bad and I'm not a novice I've only ever had a stick n only had to replace 1clutch after 8yrs of driving it. 

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## XtremeRevolution (Jan 19, 2012)

Rockerxink820 said:


> Well I was having that problem as well but it also went from 3-4 they said it was the syncro and replaced the whole transmission. Now after about 13*** miles in the new transmission I m seeing g the problem again with my 1-2 high rpm shift it grinds so bad and I'm not a novice I've only ever had a stick n only had to replace 1clutch after 8yrs of driving it.
> 
> Sent from my DROID BIONIC using AutoGuide.Com Free App


I would take the car back to the dealer, and file a case with GM about it. Not much else you can do really.

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## Rockerxink820 (Aug 8, 2011)

Well I'm actually going to my dealership today be a use my trunk button quit working so il bring it up then

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## David1 (Sep 16, 2011)

What is it with grinding transmissions and GM? I just drove a Buick Regal Grandsport manual with a couple hundred miles on it and it grinds 1-2 even with the trans warm. It's a shame since the shifter is so nice to use.


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## cmackvr6 (Mar 5, 2012)

Mine does this too. It doesn't like to be rushed.


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## sciphi (Aug 26, 2011)

This transmission really is touchy. No other way to describe it, it's touchy. If it's being driven fast, it needs a "ham foot" mashing the clutch to the floor and then being delicate to release the clutch on a really fast, high-RPM 1-2 shift. Normal driving is fine, but quick driving really does need a different driving style with this transmission.


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## Chevy Customer Care (Oct 29, 2011)

Rockerxink820 said:


> Well I'm actually going to my dealership today be a use my trunk button quit working so il bring it up then
> 
> Sent from my DROID BIONIC using AutoGuide.Com Free App




Rockerxink820,
Please keep me posted on the progress with your dealer. If you have any questions, comments or concerns please feel free to contact me anytime.
Thank you,
Stacy Chevrolet Customer Service


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## Rockerxink820 (Aug 8, 2011)

Chevy Customer Service said:


> Rockerxink820,
> Please keep me posted on the progress with your dealer. If you have any questions, comments or concerns please feel free to contact me anytime.
> Thank you,
> Stacy Chevrolet Customer Service


I will I have to make an appointment for them to check it out its just a bit disheartening because I love this car but out of any gm vehicle I've owned this one has given me the most problems 

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## Craze Ramesha (Sep 15, 2012)

I, too had experienced grind 1-2 in my previous Cruze - 2.0 lts, 5 Gears, also wheel alignment happens very quick and frequently


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## PureEnergi (Aug 22, 2012)

the 6mt is JUNK. im on my second one at 17k miles.. soon to be third. tranny is trash. factoid


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## obermd (Mar 3, 2012)

Craze Ramesha said:


> I, too had experienced grind 1-2 in my previous Cruze - 2.0 lts, 5 Gears, also wheel alignment happens very quick and frequently


I suspect the North American Cruze uses different wheel alignment hardware. We don't seem to have the alignment problems you've had.



PureEnergi said:


> the 6mt is JUNK. im on my second one at 17k miles.. soon to be third. tranny is trash. factoid


I bet it's not your transmission. Something else isn't lined up properly. Unfortunately you'll need to get GM to actually send a powertrain engineer to your dealership to track this type of problem down. Before getting the transmission replaced again, open a problem report with GM.


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## Cruzer45 (Feb 12, 2013)

Have you experienced any kind of issue with the manual gearbox in 1 2 and 4th i seem to hear more and more ppl have trouble with some kind of grind noise


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## obermd (Mar 3, 2012)

Cruzer45 said:


> Have you experienced any kind of issue with the manual gearbox in 1 2 and 4th i seem to hear more and more ppl have trouble with some kind of grind noise


Not sure who you're asking but here's my answer. No problems with 4th gear in either of my Cruzen. 1-2 in my LS is clean. 1-2 in my ECO will grind reliably on a hard fast shift from a 1st gear WOT. If I pause about a quarter second halfway down on the clutch during the WOT 1->2 shift before slamming the clutch to the floor it doesn't grind.


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## Rocco611 (Jan 19, 2013)

Mine does the same thing on a quick 1-2 upshift. I attempted to take it to the dealer to have them check it out before trying a different lube. they hit me with a $110 estimate to diag it. the service adviser seemed to think it could be the clutch , a rock had hit the oil pan or a number of other things that would not be covered under the powertrain warranty. I was willing to pay them a few of 10ths of an hour to test drive it and let me know what they could do , but not a $110 . they said they had never heard of this problem with the cruze manual transmission. I guess giving customers high intitial estimates is a good way to minimize warranty costs. definately scared me away from their service dept.


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## obermd (Mar 3, 2012)

Rocco611 said:


> Mine does the same thing on a quick 1-2 upshift. I attempted to take it to the dealer to have them check it out before trying a different lube. they hit me with a $110 estimate to diag it. the service adviser seemed to think it could be the clutch , a rock had hit the oil pan or a number of other things that would not be covered under the powertrain warranty. I was willing to pay them a few of 10ths of an hour to test drive it and let me know what they could do , but not a $110 . they said they had never heard of this problem with the cruze manual transmission. I guess giving customers high intitial estimates is a good way to minimize warranty costs. definately scared me away from their service dept.


If you can reliably reproduce this go to a different dealership and have the service advisor ride with you while you do it. I can grind on demand, even with the clutch all the way to the floor.


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## newsguy99 (May 24, 2013)

The only time I actually grind, is when I down-shift from 2 into 1.. If I'm not a full stop, it'll grind if I try putting it in first. I'm not a fast shifter either.. 

The only other issue I have with this clutch, tranny, is that once in awhile, it feels like 1st slips a little.. I'm at a stop light, in first, take off, slowly, and before I hit 1500 rpms, it seems to loose grip.. Only happens when the road goes upward (or on a small hill).. Going down, no issues.


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## obermd (Mar 3, 2012)

newsguy99 said:


> The only other issue I have with this clutch, tranny, is that once in awhile, it feels like 1st slips a little.. I'm at a stop light, in first, take off, slowly, and before I hit 1500 rpms, it seems to loose grip.. Only happens when the road goes upward (or on a small hill).. Going down, no issues.


What octane are your running and have you corrected your spark plug gaps (0.028 - 0.035")? Before I adjusted my plugs to 0.035" I felt my clutch was slipping on most hard up hills.


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## tracepk (Aug 20, 2013)

I keep hearing about this issue a lot, I'm a salesman at a dealership and as such drive cruzes frequently including the one I own and have NEVER experience any grinding. Nor have I heard anything from other dealers or gm reps about the issue. At this point I'm about 99.9% sure people just can't drive. 


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## XtremeRevolution (Jan 19, 2012)

tracepk said:


> I keep hearing about this issue a lot, I'm a salesman at a dealership and as such drive cruzes frequently including the one I own and have NEVER experience any grinding. Nor have I heard anything from other dealers or gm reps about the issue. At this point I'm about 99.9% sure people just can't drive.
> 
> 
> Sent from AutoGuide.com Free App


I am 100% sure that this is a design flaw and a result of crappy transmission fluid. This does not have anything to do with people not being able to drive. I've been here long enough to know as much. 

When switching to Amsoil Synchromesh greatly alleviates the problem, it's not driver error. There is a long poll on this discussing how many people have this issue and at what mileage. We have people that can reproduce this grind in demand. The gear changes are too far and the synchros don't function with the factory fluid, causing the grinding. Like I said, not driver error.

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## obermd (Mar 3, 2012)

I have tried to grind three different Cruzen. I can grind my 2012 ECO MT on the 1->2 shift. My 2012 LS MT and my older son's 2013 ECO MT don't grind. Even when I hold the clutch down for several seconds my ECO MT will grind this shift. All I have to do is stutter my clutch down motion just slightly on this shift and my gears will not grind. This isn't a case of knowing how to drive a stick shift. I learned on Alfa Romeos, which had a very twitchy clutches.

The ECO MT has a very close tolerances for the synchronization of the 1->2 shift and a "slow" clutch system. As a result a small number of ECO MTs will grind when shifting too quickly on this particular shift. Unfortunately I don't believe that there are enough cars showing this behavior nor is there really anything that GM can do to fix it. Your best bet if you have one of these cars is to learn to shift slightly slower and/or swap out your transmission fluid with a better fluid.


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## newsguy99 (May 24, 2013)

obermd said:


> What octane are your running and have you corrected your spark plug gaps (0.028 - 0.035")? Before I adjusted my plugs to 0.035" I felt my clutch was slipping on most hard up hills.


yes, already changed to the .035 plug spec... and I run 93 octane..


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## Rocco611 (Jan 19, 2013)

obermd said:


> I have tried to grind three different Cruzen. I can grind my 2012 ECO MT on the 1->2 shift. My 2012 LS MT and my older son's 2013 ECO MT don't grind. Even when I hold the clutch down for several seconds my ECO MT will grind this shift. All I have to do is stutter my clutch down motion just slightly on this shift and my gears will not grind. This isn't a case of knowing how to drive a stick shift. I learned on Alfa Romeos, which had a very twitchy clutches.
> 
> The ECO MT has a very close tolerances for the synchronization of the 1->2 shift and a "slow" clutch system. As a result a small number of ECO MTs will grind when shifting too quickly on this particular shift. Unfortunately I don't believe that there are enough cars showing this behavior nor is there really anything that GM can do to fix it. Your best bet if you have one of these cars is to learn to shift slightly slower and/or swap out your transmission fluid with a better fluid.


I agree that there probably hasn't been enough complaints about this problem yet for Gm to address it. the fact that changing to a different fluid reduces the problem seems to indicate a problem with the block rings ability to match the shaft speeds under certain conditions. different fluids have different combinations of friction modifiers, one that is a little less or little more slippery can certainly effect how well the block rings can do what they need to do . I dont think the Gm fluid is necessarily a bad fluid, but from reading other threads about this problem there are other fluids are better suited to this transmissions quirks. changing to a different fluid is not a fix, but seems to be a short term solution, I am going to try it anyway. Hopefully GM will come up with a fix.


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## Merc6 (Jun 8, 2013)

Rocco611 said:


> I agree that there probably hasn't been enough complaints about this problem yet for Gm to address it. the fact that changing to a different fluid reduces the problem seems to indicate a problem with the block rings ability to match the shaft speeds under certain conditions. different fluids have different combinations of friction modifiers, one that is a little less or little more slippery can certainly effect how well the block rings can do what they need to do . I dont think the Gm fluid is necessarily a bad fluid, but from reading other threads about this problem there are other fluids are better suited to this transmissions quirks. changing to a different fluid is not a fix, but seems to be a short term solution, I am going to try it anyway. Hopefully GM will come up with a fix.


My interpretation is fluid quality Xs miles driven on it and how much we actually have in the trans is the issue. A new fluid change could fix heat build up and the fact some of us are only running 1.1 qts instead of 2 off the assembly line. No dipstick is irritating and I spent more time looking for that than people looked for the trunk and fuel door buttons inside the car.


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## XtremeRevolution (Jan 19, 2012)

Rocco611 said:


> I agree that there probably hasn't been enough complaints about this problem yet for Gm to address it. the fact that changing to a different fluid reduces the problem seems to indicate a problem with the block rings ability to match the shaft speeds under certain conditions. different fluids have different combinations of friction modifiers, one that is a little less or little more slippery can certainly effect how well the block rings can do what they need to do . I dont think the Gm fluid is necessarily a bad fluid, but from reading other threads about this problem there are other fluids are better suited to this transmissions quirks. changing to a different fluid is not a fix, but seems to be a short term solution, I am going to try it anyway. Hopefully GM will come up with a fix.


I wouldn't really call it a short-term fix if it for any practical purposes resolved the issue. That's not to say there isn't a design flaw though. Change it out every 40k and you're good to go. I sell the Amsoil Synchromesh for $33 shipped and unless you have seen threads I haven't, it works better than any other fluid we've tested. Whatever you do, don't use RP or Redline's 75w-90 gear oil as it will not work as well. RP is actually not any better than stock. 

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## Gus_Mahn (Aug 16, 2011)

There is something very odd about the 2nd gear syncro. When mine failed, it would upshift the same as new (which is to say, grind at high rpm, fine if shifting slowly), but it would grind like crazy on downshifts. I've driven stick and worked on cars for 30 years and have never seen this behavior by a syncro. It's a crappy design. Same old GM. They will fix it the year before they redesign the car.


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## XtremeRevolution (Jan 19, 2012)

Gus_Mahn said:


> There is something very odd about the 2nd gear syncro. When mine failed, it would upshift the same as new (which is to say, grind at high rpm, fine if shifting slowly), but it would grind like crazy on downshifts. I've driven stick and worked on cars for 30 years and have never seen this behavior by a syncro. It's a crappy design. Same old GM. They will fix it the year before they redesign the car.


Considering mine has never made a 1-2 shift grind in the 30k miles I've owned it, I'd say they fixed it already. 

I usually avoid saying something like this, but even with the factory fluid, I never had the grind. Seemed to be very common with 2011 and early production 2012 models. 

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## sciphi (Aug 26, 2011)

I can get my 2012 Eco MT to do the 1-2 grind on demand when running higher than stock power levels. Otherwise, it's fine. 

The best "fix" for the 1-2 grind and the 4th gear rattle is to swap out the OEM pond swill/tobacco juice/sour milk/whateverothernastyfluidcomestomind with Amsoil Synchromesh. Drain out the old stuff, pour in 2 bottles of Synchromesh, enjoy. 

The other fix is adjusting the nut behind the wheel. Go slower on the 1-2 shift, and don't let the car get much above 5000 RPM in 1st. Easier said than done considering how short 1st is, and how large the gap between 1st and 2nd is.


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## Gus_Mahn (Aug 16, 2011)

XtremeRevolution said:


> Considering mine has never made a 1-2 shift grind in the 30k miles I've owned it, I'd say they fixed it already.
> 
> I usually avoid saying something like this, but even with the factory fluid, I never had the grind. Seemed to be very common with 2011 and early production 2012 models.
> 
> Sent from AutoGuide.com App


I'm sure ours is a very early 2012 that we purchased in Aug 2011. Both transmissions shifted smoothly with little effort. The replacement trans about a year ago seems a little better as far as grinding goes, but it's not perfect.


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## XtremeRevolution (Jan 19, 2012)

Gus_Mahn said:


> I'm sure ours is a very early 2012 that we purchased in Aug 2011. Both transmissions shifted smoothly with little effort. The replacement trans about a year ago seems a little better as far as grinding goes, but it's not perfect.


Get some Amsoil synchromesh in there then!

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## Merc6 (Jun 8, 2013)

newsguy99 said:


> The only time I actually grind, is when I down-shift from 2 into 1.. If I'm not a full stop, it'll grind if I try putting it in first. I'm not a fast shifter either..
> 
> The only other issue I have with this clutch, tranny, is that once in awhile, it feels like 1st slips a little.. I'm at a stop light, in first, take off, slowly, and before I hit 1500 rpms, it seems to loose grip.. Only happens when the road goes upward (or on a small hill).. Going down, no issues.


Yeah I let the shifter sit there halfway in the 1st gear gate and let the trans suck it in when it wants to. 1st while moving was not going to happen with this car(or at least mine) without excessive force so I left that issue alone. As for the hill I kinda get that at random times but can't re- create the scenario again.


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