[FrankM]

I now have ~ 12Kmi on my '15 Z51 M7. When new and not being aware of possibility of popping out of 1st gear, and also while being engaged in conversation and not paying attention to 1st gear engagement, the trans did pop out of 1st gear several times. But now being aware of that possibility, I pay more attention to the feel and location of the shift. I may have to re-depress clutch and go back into 1st gear when this occurs about once every two weeks.
I believe that some of the problems experienced by others when shifting from 1st to 2nd gears when engine is cold, stems from them being too slow and careful when shifting. I get up to ~ 1500 rpm in 1st and then do a quick pull-down to shift into 2nd gear before the rpm can decrease much. No more problems shifting 1st to 2nd when cold. Proviso: I still have on the Cup 2 OEM tires,so my cold weather driving is only at temps >/= to 40 deg. F.

Correction: Today I noticed that my rpm when shifting from 1st to 2nd is 2000rpm. My 1500 rpm estimate yesterday (above) was a bit low.
I don't know if CAGS will prevent the shift at that rpm, but I have a CAGS bypass installed, so it's no problem.

 

[mbaessler]

No problems shifting. Don't get caught with skip shift to often or just shift through it. It is a lot milder (skip shift) then my Challenger. I installed the eliminator on the Challenger. So far on the Vette no issue really. Usually just run the RPM past the issue.
Mike

 

[JFJr]

Now have ~ 12Kmi on my '15 Z51 M7. When new and not being aware of possibility of popping out of 1st gear, and also while being engaged in conversation and not paying attention to 1st gear engagement, the trans did pop out of 1st gear several times. But now being aware of that possibility, I pay more attention to the feel and location of the shift. I may have to re-depress clutch and go back into 1st gear when this occurs about once every two weeks.
I believe that some of the problems experienced by others when shifting from 1st to 2nd gears when engine is cold, stems from them being too slow and careful when shifting. I get up to ~ 1500 rpm in 1st and then do a quick pull-down to shift into 2nd gear before the rpm can decrease much. No more problems shifting 1st to 2nd when cold. Proviso, I still have on the Cup 2 OEM tires,so my cold weather driving is only at temps >/= to 40 deg. F.

I’ll try the faster 1-2 shift while the transmission is cold. I have about 2,200 miles on the odometer and noticed the shifter becoming smoother, or maybe I’m just getting more used to it. It certainly is not as smooth as the TR6060 in my CTS-V. Have any of you experienced more smoothness with the TR6070 as time and miles go by?


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[Z28+23]

I haven't driven a manual in quite some time. With my 2015 Z51, 1-4 is fine. The spring mechanism forces you to be very intentional shifting from 4-5 and not end up in 3rd. Same for 5-6 not ending up in 4th and lastly 6-7 not ending up in 5th. Same situation shifting all these patterns in the reverse sequence. I have only driven it 1,100 miles and 800 of those were interstate bringing it home so I obviously will do my part better as I get more miles in. I love the rev match feature. Particularly useful for someone who hasn't driven manuals in a very long time.

 

[Fleet]

OMG! This is the best MT ever! And I driven quite a few.

"Tell Me It Ain't So"

If the rumors about 2020 are correct, enjoy this MT while you can because it will be the last.

 

[Jerry U]

Although they're minor, and I far prefer it to the A8, the M7 does have some issues. They've been well reported in various threads. For me the shifter is just not as smooth as it should be, including very rough cold shifting into second. Also, under heavy power it's too easy to miss some gates.

Hmm, to each their own BUT it's the inefficient A8 "slush box" that has torque converter and overheating issues!

Although I'm not happy that the C8 I plan to get will not have a third pedal it will at least be an efficient, helical spur gear transaxle from Tremic (folks who make the M7) with dual clutches, computer activated. Hopefully they will be two dry clutches and not be, automatic trans type multiple disk, less efficient, heat generating wet clutches.

Just Sayn'!

 

[STINGmole]

Tremec is why I have the A8. They have horrible shift quality, the dreaded 1-2 "cold crunch" in low temps, etc. It's a miserable transmission in any car (Mustang, Camaro, Corvette).

The A8 has its own problems, but when working (which is never if you ask anyone with a manual) is far from a "slush box".

Edited to add: I'm not trying to fuel the manual vs auto debate. I enjoy both, and would have likely chosen the manual in my C7 if it wasn't a Tremec. That being said, I don't feel I'm much better off with the A8 after reading about everyone's problems with it.

I hope that going forward, GM chooses better transmissions for both auto and manual cars.

 

[texhawk]

Must remember that you are moving some massive gears around in a heavy duty Corvette transmission, and comparing the shifting to much lighter duty transmissions in some of the foreign cars... Could be at least part of the reason the other cars seem to have mch lighter shifter effort, and maybe even distance..

My shifter works fine with the Stingray transmission... just have to get the feel of when it fully engages.

 

[jimp94605]

The gates are small the also cause missing shifts up and down. I personally go 1st to 3rd, 5th and 6th. Almost never use 7th except on interstates and flats like Nevada. Always engage rev match, out of habit “riding motorcycles” I burp the throttle even with rev match.

When releasing the clutch there is a awkward noise but as I slowdown it goes away. The drive train is a weakness.

 

[Jerry U]

The gates are small the also cause missing shifts up and down. I personally go 1st to 3rd, 5th and 6th. Almost never use 7th except on interstates and flats like Nevada. Always engage rev match, out of habit “riding motorcycles” I burp the throttle even with rev match.

When releasing the clutch there is a awkward noise but as I slowdown it goes away. The drive train is a weakness.

If you can't break the habit of "blipping the throttle" yourself, don't engage rev match as when the throttle is anything but fully non depressed it cancels. Depending on your blipping timing and how close a match you are making, it could mess things up!

I always "blipped the throttle" in my cars as I have had only standard shifts for my DD in 60 years of driving. I did a good job when downshifting where the rpm's would be high in the lower gear. However, especially with my C6 when downshifting at lower rpm's like the 5th to 3rd from 45 mph when making a turn I got it "perfect" half the time! Not as easy to modulate the throttle to get a "perfect match" going from 1500 rpm to 3000. I have learned not to 'blip" and let rev match do it perfectly "every time!"

 

[white_out]

Must remember that you are moving some massive gears around in a heavy duty Corvette transmission, and comparing the shifting to much lighter duty transmissions in some of the foreign cars... Could be at least part of the reason the other cars seem to have mch lighter shifter effort, and maybe even distance..

My shifter works fine with the Stingray transmission... just have to get the feel of when it fully engages.

I suspected this was the case; compared to the smaller imported cars I have owned in the past, the C7 M7 feels more like a truck transmission, and then I thought, it not only is handling more power and torque than any of my previous cars, but it is also designed for some very heavy use (like at dragstrips).

With not quite 20k miles on the car, I have learned to live with the M7 quite happily. Shifting was much stiffer initially, but it got smoother after the first 1000 miles or so. No problems noted in colder weather, and never any issues with popping out of gear. In ordinary driving around town (sometimes somewhat spiritedly), finding 5th gear is always a bit uncertain. When lateral g-forces are involved, it becomes less likely that I will find 5th on the first couple of tries. I have to think that this characteristic is why Consumer Reports described the shifter as being "vague". At the same time, the spring-loaded 3-4 gate is very helpful on the track, as I do not think very many tracks would require an upshift to 5th. (at over 150 mph, right?)

Again, not wishing to stir up the endless "manual vs. automatic" debate, my own experience in purchasing my Grand Sport was going to our local Chevy/GM dealership and test driving a Stingray. The Sales Manager explained to me that they only stocked automatic transmissions because "that is what most people want". I got a feel for the power output of the LT1 by stabbing the throttle on an uphill onramp to a divided highway. The acceleration was brisk and invigorating, but the slight delay between hearing the engine make power and the seatback pushing against my back just reminded me of my '64 Impala with a 283 and a two speed Powerglide transmission. No, the A8 does not really deserve to be called a "slushbox", but it kind of is. And none of this matters to folks who have never driven anything but automatics. While I like the quick shifts that the A8 offers, I would still want a real clutch and a real third pedal on the floor. So, I spent some time talking with the Sales person, and decided to order my GS from the factory with an M7 and everything else that I had decided by then that I wanted on the car. So, I decided on the M7 without ever having driven one, and was pleasantly surprised to see the "current gear" indicator on the DIC and the HUD, so I can be sure of the gear before I let out the clutch. Yes, I gave up the convenience of remote starting, but this is a sports car, after all!

So, I voted "yes" on problems, but only because the actual gear selection is sometimes uncertain. Maybe anything having more than 6 gears should be a sequential shifter anyway. Even with a Ferrari-type gated shifter, you would still have to look down to see which gate you were going into. (Not that I have ever driven a Ferrari.) The forced 1 --> 4 shift is irritating, but it does not come up very often for me, and I can overpower it in most cases, so not really a complaint, especially since I didn't have to pay a gas guzzler tax.

 

[regguy1]

FYI: 12000 miles ago I drained the factory ATF and refilled the M7 with 5w20 Mobil1 motor oil. It has never worked better.

Some background: I worked as a transmission rebuilder for 45 years, owned and operated my own shop for 40 of those years. I regularly used motor oil in manuals that had ATF from factory.
Never one problem in the hundreds of times I've used the motor oil in MT's , better lubrication than ATF.

 

[snakeman48]

Well I just checked yes on the poll.
I just lost the 5th gear synchronizer. 2651 miles on the car. 2016 Z51. Just happened with out any prior problems.

I don't drive it hard or beat on it, but I do like to run it up to 4,5000 rpm when going through the gears. Mostly drive around in 5th, using the other 2 for highway, interstate speeds. If I shift like a grandma, it goes into 5th without any issues, but if I spiritedly the car with part throttle, well I get massive gear clash before it goes in.

Local Chevrolet dealer, who I use for service on the car, can't fix it as his corvette tech died of a heart attack, and they don't have all the necessary tools to do it.
Going to check the next largest Chevrolet dealer who still has a corvette tech.

Damn my luck. :moody:

 

[Mobius]

FYI: 12000 miles ago I drained the factory ATF and refilled the M7 with 5w20 Mobil1 motor oil. It has never worked better.

Some background: I worked as a transmission rebuilder for 45 years, owned and operated my own shop for 40 of those years. I regularly used motor oil in manuals that had ATF from factory.
Never one problem in the hundreds of times I've used the motor oil in MT's , better lubrication than ATF.

I'm glad the engine oil is working out for you, but since there are some great full synthetic Dexos III ATFs out there (what the M7 tranny is spec'd for), I used Amsoil Torque-Drive.

FWIW, the viscosity characteristics between 5W20 and Dexos III are more similar than different. http://www.latchoil.com/pdf/Leverage-Specifications-for-Lubricants 4-2011.pdf

 

[TNSQUIRE]

1-2 shift when first starting out. I also installed MGW shifter. Much more precise.


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[white_out]

Well I just checked yes on the poll.
I just lost the 5th gear synchronizer. 2651 miles on the car. 2016 Z51. Just happened with out any prior problems.

I don't drive it hard or beat on it, but I do like to run it up to 4,5000 rpm when going through the gears. Mostly drive around in 5th, using the other 2 for highway, interstate speeds. If I shift like a grandma, it goes into 5th without any issues, but if I spiritedly the car with part throttle, well I get massive gear clash before it goes in.

Local Chevrolet dealer, who I use for service on the car, can't fix it as his corvette tech died of a heart attack, and they don't have all the necessary tools to do it.
Going to check the next largest Chevrolet dealer who still has a corvette tech.

Damn my luck. :moody:

That is unfortunate, snakeman48, but I feel worse for the tech who died.

 

[JoeCT]

I meant to post this earlier but during one of their seminars at Corvettes at Carlisle this year, Paul Koerner and Brittany George discussed a procedure for adjusting the shifter that can help alleviate some of the symptoms many folks describe. In fact, Paul did this on my vehicle in 2016 and it really did resolve the crunch/grind issues for me. I'll describe it here as best I can and they did say this was very do-able by an owner but that some of the dissasembly of the console that is required was tedious no matter who does it. Apparently there are some Allen or Torx bolts that once loosened, will allow the linkage to release to what I will call a "relaxed" position. My impression was that the linkage may be under tension either from assembly or initial break-in and loosening it and then retightening in that new position that it reaches serves to set it up properly. Forgive me because I'm really interpreting here so you will want to do your own research on this to find out what's really involved as far as steps and what it accomplishes.

Anyway, there's no-one better to get your Corvette advice from than those two folks and I'm happy to have Paul in my local area to service my vehicle.

 

[white_out]

I'm glad the engine oil is working out for you, but since there are some great full synthetic Dexos III ATFs out there (what the M7 tranny is spec'd for), I used Amsoil Torque-Drive.

FWIW, the viscosity characteristics between 5W20 and Dexos III are more similar than different. http://www.latchoil.com/pdf/Leverage-Specifications-for-Lubricants 4-2011.pdf

Let me start out by stating that it has been 40 years since I studied these things, but my understanding is that helical-cut gears have more sliding friction and are slightly less efficient than straight-cut involute gear teeth. Going one step further are the hypoid gears used in rear differentials. I think that the sliding friction on the oil film under great pressure benefits from some anti-friction additives that plain journal bearings do not require.

Obviously, a good lubricant will perform well in various applications, but I am just sayin' that maybe some real engineering has gone into the design of lubricants for specific tasks over the last century or so. For instance, the addition of sulfur to gear oil.

From my 0.56 seconds of searching the web:

"Sulfur is used in many EP (Extreme Pressure) oils and metal-working fluids as an EP additive. The basic way this works is for the sulfur to react at elevated temperatures, such as those experienced by meshing gears to form a sulfide layer. For example, for steel gears, an iron sulfide layer forms on the gear tooth surface. This ductile layer improves sliding contact, preventing scuffing or galling."

 

[Jerry U]

Well I just checked yes on the poll.
I just lost the 5th gear synchronizer. 2651 miles on the car. 2016 Z51. Just happened with out any prior problems.

I don't drive it hard or beat on it, but I do like to run it up to 4,5000 rpm when going through the gears. Mostly drive around in 5th, using the other 2 for highway, interstate speeds. If I shift like a grandma, it goes into 5th without any issues, but if I spiritedly the car with part throttle, well I get massive gear clash before it goes in.

Local Chevrolet dealer, who I use for service on the car, can't fix it as his corvette tech died of a heart attack, and they don't have all the necessary tools to do it.
Going to check the next largest Chevrolet dealer who still has a corvette tech.

Damn my luck. :moody:

FWIW, have a friend with a 6 bay shop that was only doing transmissions, mostly automatics, but now handles all kinds of service. He did the racing trans in m street rod. The Caddy, Chevy etc dealers in town don't keep a trained trans tech on staff since they have few failures so they bring even warranty work to him.

Even a great C7 Tech gets so few transmissions (especially standard shift) to do so cannot become skilled IMO. If on warranty I'd let the dealer decide if he'll remove and bring it to a transmission specialist (who knows standard trans repair.) If there is a problem they are responsible for making it right.

 

[Mobius]

Obviously, a good lubricant will perform well in various applications, but I am just sayin' that maybe some real engineering has gone into the design of lubricants for specific tasks over the last century or so. For instance, the addition of sulfur to gear oil.

You'll get no argument from me, and that's why I used Dexron III full synthetic (Amsoil TorqueDrive) when I changed my tranny fluid.

I'm closing in on 37,000 trouble-free miles.