Edmond

Situation: when I'm stopped, I shift into first, throttle and slowly let the clutch out.

Sometimes, maybe 1-8 times, I will hear a grind right underneath the shifter and the car will not go forward.

It only happens in first. If I'm on a decline and start out in second, it doesn't happen.

Other than the issue from 1st, every shift is fine all the way from 2nd to 6th. Shifting into R is fine as well.

Any ideas or suggestions on what the issue is?

TheDingo

Remember, always start small. A good place to start.. check your clutch fluid. If it's dirty, use the RANGER protocol until it's clear and see if that helps.

fxdl

sounds like you're not getting it all the way in gear

tricep

1st gear is always fun. Wait til it starts popping out of gear.

Do you still have a skip-shift?

fisher auto

Add me to this club! But only on my 99' FRC

The Stranger

People, PLEASE stop recommending the "ranger" method for every single clutch/transmission related problem that comes up on the forums. Maintaining your clutch fluid (which, btw would not even have to be done on the scale that Corvette owners endure if GM had engineered a good clutch system) is only a band aid solution. There are many mechanical parts in the transmission and clutch system that can go bad, and keeping your clutch fluid clean regularly only keeps any developing problems at bay for that much longer.

TheDingo

Lots of people's problems have been solved using that method. It does sound like there are bigger problems, but it's a good place to start. The bottom line is GM engineered something that does need band aid fixing every now and then. To say that using that protocol to prolong a problem is a bad idea is an ignorant statement in my opinion... that's the whole idea of regular maintenance. why would you even want to keep dirty fluid in your system? wow.

The Stranger

I stated that using that method will only keep any developing problems at bay for a while longer.

Case in point - My own experience. I regularly maintain everything on my car. For the past 20k miles (ever since I owned my z06) the clutch fluid has never seen the slightest amount of dirt. I literally changed it every week to every 2 weeks or so. Guess what? Not only did my transmission become hard to shift into first, it has now developed a serious grinding if I try shifting into first.

Keeping your clutch fluid clean should be part of regular maintenance. In my opinion, it is not a solution once other problems become apparent.

ZR1991

This happens to me occasionally, and is is easy to fix. The noise you hear is the trans jumping out of gear, and as already pointed out, can really be startling.

There is apparently no discussion in the owners manual, but in my older ZR1 manual ( with the terrific ZF trans), the discussion was to the effect that the gears in that specific transmission were cut differently, and sometimes were hard to put fully into gear at a full stop. The solution is to let the clutch out momentarily in neutral to spin up the gears and the first gear will fully engage. That will solve the problem 100% if the trans is not damaged. And you don't need to do it every time, just when the shift into first 'feels wrong". For me, once or twice a day, usually when stopped for some time at a light, or if i don't shift immediately upon stopping.

In the ZR1, the reason for the different cut on the gears was for added strength. I would not be surprised if the ZO6 had a similar issue, but the issue, to some degree or other, can relate to any manual transmission.

Hope this is helpful............

tricep

O.k then...


Most of the teeth on your clutch plate look like a homeless person's teeth.

Edmond

That's what it feels like at times.

What I did today was try something different. Shifting into 2nd is much easier than shifting into 1st. So what I did at the light was shift into second and then shift up into 1st before I took off. Haven't had an issue with it since.

If it makes any difference:

Trans fluid is Amsoil Universal ATF
Gear fluid is Amsoil GL-4 75w-90

I just put it in last weekend.

It was cold here this morning so shifting was a little more work, I expect that though because it's the same way in my '08 tC with the 5 speed.

Coming back from base, I drove the car harder. Still shifts damn smooth all the way to 6th when I run the car harder. Don't know why...

Can I damage the trans by starting in 2nd?

TheDingo

No.

The Stranger

This may be a totally redundant question, but did you have problems shifting into first AFTER you switched to Amsoil, or was this issue present prior to the oil change?

Edmond

Prior to.

I assumed that the fluid in there before was the factory fill.

Eddie 70

I use 2nd gear about 80% of the time starting off in mine. I too am running Amsoil in the rear and in the trans.

The Stranger

Do you get any grinding with 1rst gear?

I have (had) about 2k miles, maybe less on the Amsoil fluid. Once I got the 1rst gear grind it happened quite a few times before I just gave up and started putting the shifter into 2nd prior to engaging 1rst.

Last night I dumped the Amsoil fluid out. Looked at it for shavings and found nothing. Then I went through the fluid with a magnet. Still no shavings. I replaced the Amsoil with Penzoil ATF. We'll see if there is any difference with this 1rst gear grind after a couple hundred miles, but I'm not keeping my fingers crossed.

Eddie 70

I do not get any grinding going into any gear but sometimes it is harder to get it in 1st completely if I am not paying attention. I have to be completely stopped and may have to let out on the clutch or roll the car to get it completely in gear. I never try to force it into gear. Changing the fluid is easy enough to do I have entertained changing it once a year even though I know it does not need it.

ZR1991

As I posted earlier, this is correct info, and changing fluid, allowing warm up, and such can make it better. But generally, regardless of the generation of Corvette, the higher horsepower models (ie The older ZR-1, and the ZO6) can exhibit these symptoms to some degree, and it is literally related to the gear cuts necessary to bolster strength while fitting in the same package as the standard car. So I would not worry about it. it is more something to be aware of and to understand. When I owned my ZR-1, I was really involved, and found the tech bulletins about it. It is also common in marine out-drive applications where the package size is restricted. As I visit my old buddies on the ZR-1 forum, I will try to find the reference to it. It makes for interesting reading.

Regards,

Edmond

So this is a problem that could also be in all the C6 models as well since they all, even in stock form, have more power than our C5 Z06's?

ZR1991

I wouldn't conclude that. It isn't about the horsepower as much as it is about the packaging and design of the original car. Take the C4 or the C5. The original 6 speed transmissions were designed to handle the power of the standard car. The packaging was then designed. In the Corvette, the packaging (which includes weight) is really critical. Then a few years later, a much more powerful model is introduced, and that requires increasing the strength of the transmission (and other components). Among other things, one way to gain strength in gears is to make them more "square cut", but keep the same size. the trade off is some shifting differences like we are talking here, and in the case of the C4, some added noise. But the packaging is maintained, avoiding a redesign, and the weight is controlled. Moving to the C6, I would presume that the base car was designed from the beginning to handle its projected power, and it is possible that the later, much more powerful cars would have these minor issues. Or they could have benefited from better design. It depends on the original design.

But in any case, these are minor issues to the people for whom these cars are meant to be sold to, because adding large performance potential to an existing design always has trade offs (another example is the different suspension geometry in the ZO6). What I was suggesting, based on what I had known previously, is that one should not be too concerned about this. it is "the nature of the beast". And obviously, what I have been describing is not the entire story. I am sure that if one of the 6 speed transmission designers got on here, he could add much more detail.

I will look for some of the ZR-1 stuff. I think it is still around.