jizay

I've read a bunch of threads about owners having a issue when shifting from 1st to 2nd or 2nd to 3rd and most people seem to say 'wait until it warms up'. I noticed a grind in my 1st to 2nd even when just driving pretty normal, maybe a little aggressive. So when the car was completely cold, I drove and did about 12 or so runs, under hard acceleration shifting from 1st to 2nd. The first run was terrible, with a loud grind going into 2nd, the remaining runs were fine, I couldnt get it to grind again. Then when driving back home, pretty normal, maybe slightly aggressive but no tire burners, the 1st to 2nd grind happened but this time much less, it was real quick and not so loud.

So is this a bad syncro. The 'wait until it warms up' doesnt seem to be an acceptable answer for a car that costs about $50k when new. Not to mention that what happens if you want to drive this car aggressively? So does this grind only happen for others when cold and then completely goes away?

onehdeagle

I think you need more practice shifting.

Wayne O

I realize it was a test but doing 12 "hard runs" when the car is completely cold isn't the best thing for your car. I'd wait on the WOT until you reach an acceptable operating temp.

The problem itself could be due to various things...it could be user caused by 'rushing' a shift...it could be a clutch or a transmission issue. When's the last time you checked or changed the transmission fluid? Syncro's need oil...I'd start with flushing and changing both your clutch and transmission fluid and then see what happens.

Try a static shift test going through the gears with the engine off...see how it feels. Do you note any grinding just going through the gears normally?

I've never had any problems with my 2005 MN6 but I did switch to Royal Purple transmission fluid some time ago. It works well for me. Good luck and let us know what transpires.

jizay

Nice, but I don't think technique is the problem. Good input though.

I've had a C5 for 6 years, have had this one for 5 days and still deciding if I should keep it. The car had only sat for an hour or so after I'd been driving around town for about 2 or 3 hours before the runs were done. During the these test runs I was very conscience to make sure that I wasnt shifting before engaging the clutch and wasnt disengaging before completing shifting. I originally noticed a slight grind while doing some normal driving, so I thought I'd put some power to it and see how it handled it.

jizay

So do you ever do any hard 1st -2nd gear shifting at 5500 rpm?

I'm not street racer, this car will be my daily driver. I've had a C5 for 6 years and drove it to and from work every day for an 85 mile round trip commute. I just don't love the idea of having a tranny issue on a car with 20k miles. I have read quite a few posts here though that have talked about shifting issues, but most of them sound like they only happen when the tranny fluid is 'cold'.

AORoads

I agree with Wayne, who has put it very nicely. You've done nothing nice to this car that isn't yours by hurrying the shifts in order to "test it out" when it's cold. I would do as he says; change the clutch fluid, change the trans fluid, in case you didn't notice what he said. Then try it.

If you talk to anyone who knows something about transmissions, you will find out that they are all different in design. A grinding of gears in a $50K car is no different than if it happens on a $20K car (and it does) or a $150K car (and it does). It's the design and intent. The way you treat that type, or any type of transmission, will determine how long it lasts.

This trans may have a synchro issue as you suggest because the prior owner used to consistently test it out just as you have. Or, it could be babied, and normal. No one will know until you do what Wayne suggested, short of a complete teardown.

talon90

In my opinion, any vehicle when driven aggressively immediately upon startup is likely to behave in ways that are not common during normal operation of the car. You are doing the car no favors by slamming through the gears before the fluids have at least come up to normal operating temperatures. A cold shift at 5,500 is very hard on the transmission and clutch as the viscosity of the fluid is not where it needs to be.

The characteristics of a grinding when cold is more prone to the 2008 Tremec T6060. The 2005 T56 really shouldn't be exhibiting those characteristics. I have a 2005 and have never had a grind on the 1 to 2 shift. The transmission and clutch arrangement in the 2005 C6 should be very similar to your C5 and as you can recall from your C5 it didn't happen with it either.

If you are comfortable with shifting the T56 and you feel that it isn't technique related to either your shift or your clutch then I'd say that there is something that needs to be looked at on the car.

AutoCutter

I don't think it is a bad syncro because a lot of people have this issue and not only when the trannie is cold. I do think it is a design issue with the Tremec's(sp?) I wonder if Viper owners have this issue too since they have the same trannie?

Jim Nebraska

Yikes....I am not considering selling my existing '05, but this story sure gives me the heebie-jeebies. Imagine, in good faith, allowing a prospective buyer, to test drive your car...only to find he/she is deliberately hot-testing a cold car! "Thanks for letting me try out your car....I've decided not to buy it. Oh, by the way, the transmission, or what is left of it, seems to be making a lot of "funny" noises!"

C6~Missle

Never had any gear clash issues with a T56.. Had 3 vettes with the T56...
The 6060 in the 08 seems to be more sensitive to being rushed when cold... but now after some miles.. it does not exhibit any problems... but.. I never rush the shifts until its fully warmed up... I never did that with the T56 either..
When I owned a mitsubishi POS some years ago.. it came from the factory with a 1 -2 crunch.. it finally went away when I sold the POS.

not08crmanymore

There are written facts out there about tough shifting in the 05's.Bring it to the dealer and check the SYNCHRO.Some have changed fluids to ROYAL PURPLE or something which eased it up a bit.

THECRAIGMEISTER

I live in Wyoming. It has already snowed around 12" last week. It is very cold and I have been meaning to switch my trans fluid and try Royal Purple. When I go for a ride in the winter or even a very cool night in the spring or fall I find myself double clutching for awhile because the tranny is so stiff. It takes quite awhile for it to warm up and shift normally. It catches between gears and doesn't want to engage. It takes awhile to get used too. Now that I double clutch and am used to it I don't even really think about it much. Just know that when it warms up it will shift as it is supposed too.

jizay

Thanks for the input everyone. I'll give the RP a try, that sounds like it worked for some of the folks experiencing similar issues.

I'm sorry if I wasn't clear in the first thread but the car wasn't 'cold'. We had just been driving around for a few hours, and on the way home driving normally the car had a slight grind into 2nd. I just wanted to give the car an honest test drive, which in my opinion does allow for some aggressive driving. So after about an hour I went back and and put some of the power of this car to use.

Im not trying to be a d!ck or anything but it seems odd that so many people are tolerant to the idea that this car's tranny can't quite handle the power the engine puts out. If I'm misinterpreting the posts than I apologize, my original question was in regards to what I was experiencing and the multitude of other posts that were similar but not quite the same as what I was seeing.

The sixth gear synchro in my C5 was bad or worn or something, I had to double clutch to get it into sixth without grinding if I was over 1500 rpm. I put Amsoil in the tranny and it seemed to help a little, but not much.

By the way, I wouldn't let anyone 'borrow' my car that's for sale without me there. At the same time I would expect the potential buyer to get on it and experience the car. This vehicle was a carmax vehicle and from what I've read here some people have not had very good experiences with carmax. I just wanted to make sure the tranny wasnt going to fall out or need a rebuild after I had it for a month.

Rich Farr

My poor shifting 2005 vert shifts great after:
1. getting the clutch fluid clear - took three cans of fluid
2. anti-venom method - 3/16" copper washer to reduce tension
3. synthetic atf - Amsoil

Please contact me if anyone needs details.

Rich Farr

jizay

I used Amsoil in my 98 and it seem to help things shift smoother. I also did the copper washer trick too. In the 98 I had an extension line with bleeder tip installed so that I could completely flush out the fluid. The 05 doesnt have that, so I guess I'll have to do the turkey baster method.

I'll probably give the RP Syncromax a try and definitely flush the clutch fluid. I think I still have one more of the washers left too.

Thanks.

Irv

Having tried both, Redline D4ATF works better for cold shifting than Synchromax. Nonetheless, the symptoms sound like a bad synchronizer.

70454

This may be a stupid question or an inability to read every word here, but does the OP still have the 1-4 shift CAGS?

torquetube

I thought you were perfectly clear. This is what you wrote: "so when the car was completely cold, I drove and did about 12 or so runs, under hard acceleration shifting from 1st to 2nd."Who suggested that?

Your original description of shifting hard in a "completely cold" C6 and your accompanying remark that for $50K you shouldn't have to warm up a transmission, plus your confession that "the sixth gear synchro in my C5 was bad or worn or something, I had to double clutch to get it into sixth without grinding," strongly suggest a pattern of abused gearboxes.

Also, the C6 and C5 gearboxes can only be warmed-up by driving. They don't get much heat from the engine.

S2K

I have not had that experience in over 50k on my '05 C6. At first 3rd gear was tough only because I wasn't use to the motion needed in the C6. In my previous 6-speed 3rd gear needed a little diagonal motion, but in the C6 you sort of push straight up from 2nd to 3rd. I have had issues at times getting the car to go back into first which can cause me to have to double clutch. Whether the car is hot or cold doesn't seem to matter with that problem.

Having said this, I did have the syncros break on me while driving in stop and go traffic on the freeway. Good time that was....

Mike's Sweet 19

I have an 2005 with 47k mi on it and the corvette mechanic that I have liked the suggestion I gave him about changing the transmission fluid at 50k mi with Royal Purple synchromesh xmission fluid. He added a suggestion to change out the clutch fluid at the same time.
FYI the Royal Purple fluid has a greater index of slipperyness and is often used by folks who race their cars.
So far I have not had a problem shifting in any gear. I do have a tendency to double clutch 1-2 and 2-3 by shifting slowly so I feel the shift lever roll past the synchro's (it a feel rather then a shift point) especially if I am caught in traffic.
Hope this helps.
Mike