patentcad

Over 40+ years of car ownership (and when I was a kid I was the guy doing the oil changes and tune-ups) I have never seen a manual tranny break on any car. Clutches wear out (I replaced one myself on my 1971 Datsun 1200 back in the day) but the transmissions don't seem to ever be problematic. Automatics are far more complex, and as we know, the C7 has had its (ahem) issues with the A8. That being said, the only clutch I ever saw wear out (or that I even ever heard of wearing out) WAS the one on that 1971 Datsun c. 1978.

I wonder what a normal life of a C7 clutch is? 200,000 miles? More?

JGarland

Many of these comments sounds really uninformed.

Mike Campbell

Interesting comments. However in my over 40 years of car ownership I recall a cluster gear going on my '64 GTO when I hit an ice patch while shifting. Had to put in a new trans. I also had my clutch go on my 99 C5 coupe. I remember getting it flat bedded to the dealer and I had it replaced with a ZO6 clutch. The tech told me he never saw a clutch that bad and it probably was defective from the factory. The car only had 18K miles on it so clutches are like tires...they wear out in time. I remember the guys in my Corvette Club asked me what did my wife have to say about this. I told them she said, "You should've got an automatic!"

davepl

It's funny to me because no one can really articulate why they like the M7 other than ambiguous terms like "soul" and "connection" that mean nothing to me because I'm not a hippie.

Now if someone will stand up and say "I enjoy listening to musical tones and pulling a lever when I hear one exceed 6200Hz" then I'd understand.

I have two TKO-600s and M20. I like to drive them because it reminds me of being 18 and lusting after the very uncommon but real four-speed cars that I saw as a kid and associated with "real" muscle cars. It doesn't make a car better or more real or the driver more manly or smarter or better.

It does, however, make a car cooler.

- Dave

(And yes, I know an engine doesn't really produce a 6200Hz tone at 6200rpm)

VetteDrmr

My main problem with a torque-converter transmission (as opposed to "auto", which DCT-type transmissions also fall into) is the heat management, or lack thereof. As best I know there hasn't been a TC-type transmission made in an OEM fashion that will run a 20 minute session on the track.

The other problem I've read about (not experienced directly) is the problem of the computer taking gear selection out of the driver's hands. Not talking about over-rev protection, that makes sense. But upshifting preliminarily or lagging the shift when commanded. It seems like most of those gremlins show up when the transmission gets hot.

This review of the ZR1 is quite interesting about both the good points and gremlins experienced by R&T at VIR:


Have a good one,
Mike

davepl

I've never had a problem with heat management that I thought was the transmission's fault. Lots of issues with engine heat management that result from the transmission keeping the RPMs in the optimal range, but that's it's job. It's supposed to do that.

M7 cars make it around the road course more successfully on hot days because the M7 driver is in the "wrong" gear a lot of time. Most should be a gear or even two lower but the torque of the LT4 is deceiving... you think you're already fast.

Although the torque converter does produce some heat, it's not of consequence compared to what's going on with the engine. Same with the blower - yes, compressing air makes some heat. But nothing like adding gasoline to it and lighting it on fire! So the A8 does have some more heat to shed, and the transmission programming is the cause of the engine's overheating, but the trans doesn't thermally overheat things if that makes sense. I don't know if that's what you even meant (that the TC overheats things) so I'm just being a bit pedantic to be sure.

pdiddy972

That's a beauty!

JGarland

Tony Kanaan driving a "soulless" auto...

pdiddy972

This reviewer doesn't seem to know that the Vette have a screen that shows tire temps and another that shows pressures. He keep guessing as to whether they're warm or not.

VetteDrmr

What I was meaning was the internal heating of the transmission itself. I can't explain the transmission's programming; it's really complex. IDK if the shifts start lagging when the trans gets hot due to software trying to manage the temps,or the actuators start losing effectiveness (i.e. they react more slowly or with less power).

But you're right; engine temps are to be dealt with by the engine's systems.

Have a good one,
Mike

davepl

I haven't noticed the shifts changing with temps, but I've only had the trans really hot once or twice. Sounds like a problem, but good luck getting a dealership to reproduce and fix that one!

Higgs Boson

the tcm modifies shifts based on temp, yessir, sure does, yep.

davepl

I wonder why, from a technical standpoint? Pressures need to go up or down when fluid temp changes? I'm not a hydraulics guy... I figure if it's not cavitating or boiling, it's good.

stephen1254

I'll give it a try. There is a level of driver involvement and control in the M7 that isn't present in the auto. It may be that there is more work involved in manually shifting gears, and that provides added satisfaction to what is largely a passive activity.

There is also the fact that an engaged clutch is a more solid mechanical connection than a TQ SOME of the time. I'm aware that a TQ "locks up" at some point, but in my experience there are upshifts and downshifts that feel "fluid," and not "solid," if that makes any sense. When you shift the manual your shift is completed when you let out the clutch. When you shift the auto there is a period - however brief - where the TQ is not locked up; it feels like a lazy shift.

While I've never driven one, I would think a DCT would combine the feel of a manual shift with the convenience of an auto. That, however, is part of my point - I don't want convenience, I want involvement.

My wife's SUV is an auto and a manual there would be silly - it's just an appliance that gets us from one place to another. I don't want involvement there. I do, however, hate that when I want it to downshift several gears for acceleration I have to accomplish that with the gas pedal and put up with the lag until it's in the right gear. It works, but not nearly as efficiently as manual shifting.

davepl

But again, all you've managed to actually say is that there is "driver involvement and control in the M7 that isn't present in the auto" without explaining or defining why any of that is good or desirable.

Even if I grant that involvement is "good" for some reason, the M7 still doesn't really offer an advantage on those grounds because the A8 can be driven manually as well.

Since the auto has paddle shifters it seems to me that if the A8 driver so desires, they can put it in M and shift it with exactly the same level of driver involvement and control. One is a paddle and one is a lever but they command the same function - change intermediate ratio. That's all.

Your notion of soft shifts and the lack of a mechanical connection are psychological. I don't have the math chops but the centrifugal forces connecting the turbine to the impeller are ENORMOUS at high rpm. There is theoretical slippage, but that's it... theoretical. If you've felt an A8 shift hard it feels purely mechanical with no sense of a fluid shift whatsoever (at power).

Same with the notion of a "lazy" shift. Have you ever been in an A8 car for a WOT 1-2 shift at 6400RPM? It cuts fuel, changes gears, and reapplies power in about 100ms. It literally BANGS you into your seat. Far faster (and more brutal) than even the best human M7 driver could approach.

So, I could say the A8 offers the same level of driver involvement all while offering better performance. I don't say that, because it sounds like I'm saying the A8 is the better car and I'm not.

I guess I'm not getting why a lever over a paddle is some amount of "involvement". If people came out and said "Yeah, they're the same thing but one is electronic and one is mechanical and it's a psychological difference only", I'd buy that.

And hey, remember I'm not saying the A8 is better, only that it's not worse. I should be able to make that stand without offending anyone.

stephen1254

Not offended at all. I'm just glad the manual option was available to me when I ordered this car. "To each his own" sounds pithy, but it's very true.

I will say that when I drove a rental A6 Vette I didn't do wide open throttle high RPM shifts. For me it was more normal driving - part throttle shifts between 3500 and 4000 rpms. I didn't like the way it shifted.

And I look at the bright side - given that the manual transmission is going the way of the Dodo bird, I have a highly effective anti-theft device in my car!

davepl

Indeed, the A6 was terrible... you can't judge the A8 based on old autos any more than I could indict the M7 based on old Saginaws!

Like you, I think the great thing is that we can get both right now. I actually predict GM will be one of the last holdouts with a true manual, but I think a DCT is almost required at this price point.

dvilin

One thing I like about the M7 is the no lift shift feature. It reminds me of the old muscle car days with the 4 speed transmissions and while racing trying to execute the speed shift.
In the Corvette I really like testing my skills by taking it to red line using the no lift shift jabbing the clutch, grabbing the next gear, then pedaling the gas as it wiggles a bit and bam hitting the next gear. Hard to put into words but it is really a different experience than what I got when testing the A8.
Not saying it is better just offers for me a stronger test of my driving skills.

Deweyox

The reason I had to order mine as well. Everything is with the with the glossy black Rustoleum paint rims. I have a Resto-Mod 1976 Trans Am that has a Tremec 6-Speed and I enjoy it immensely although the clutch has already been replaced and is being taken apart a second time because a solenoid went bad. LOL with-in in 5,000 miles.....IFSOFATSO I ordered this car with an Automatic.!!!!

theplatinumog

Okay, let me try. Did you watch Farah drive the zr1? Did you see it hit the rev limiter and bog when he pulled the paddle late? Then it upshifts itself to third and he pulled the paddle a hair late and it was in 4th. There were at least 4, maybe more, times when he was not in the gear he wanted. This would drive me absolutely crazy on track. I want control, not the car.

The argument would be feasible if the A8 auto weren't so bad. Compared to the AMG gts and 991.1 gt3 I drove on track, the zo6 a8 box I drove on track was a joke.