Ranger

Was asked by a Florida friend, who rarely visits the CF, about the sturdiness of the rear ends in the new C6Z06 given the power the car makes.

I have not experienced any rear end breakage in my current car or my two previous C5Z06s. But found one thread:

Owner Reports Third C6Z Right Side Axle Housing Failure

That owner provided PDF's of the R.O. for the three warranty repairs; They state>>>

And recall but can't find the thread from a C6Z owner who broke a half shaft on a strong shift and attached pictures of the greasy broken parts. Anyone have a link to that thread?

Any other owner experience any C6Z06 rear end issues. If so, please provide the details and Chevy's response to the issue or perhaps a link in case I missed a previous post.

TIA,

Ranger

EVIL_C5

i heard a local guy broke his sunday from dumping the clutch on he street and got wheel hop.

unsure of any other details.

Ranger

Found that missing thread.

Owner Reported Clutch Disintegration, But Turned Out to Be Failure of Right Rear CV joint Coupler Housing

I'm no parts expert, but a review of the photos in Post #56 on the cited thread indicates the right side axle shaft CV joint coupler housing is broken on bdawson82's car.

Any other incidents for other owners??

Ranger

BLU-BY-U

I'm very interested about this as well.

I'm thinking most carnage will result from severe wheel hop and a driver who doesn't really know how to react when faced with it, just the same as the old Z. Curtail that wheel hop with a smooth launch and I'm betting this car holds up as well as the last Z (which, for a few of us, took a ton of launches without breaking).

Ranger

Mine has exhibited no wheel hop in 12 passes and none on the street. But I refrain from over-spinning the rear tires. I've seen several C5Zs, one C6 and one Caddy CTV break because the drivers let them hop and then stayed on the throttle.

Just an opinion at this point...dead hooking the tires (zero spin) at a decent launch rpm (>2500) either on a prepped drag strip or the street will put serious stress on the rear end. TM on the C6 and C6Z is intended in part to reduce the impact of that.

I've always tried to avoid dead hooking; and have seen quite a few cars break while doing that.

Ranger

Another Yellow

Ranger, I'll post some interesting info about this tonight.
Frank

Ranger

Hey Frank. Will be very helpful to members to bring more of the relevant info together in this thread.

Recognize some owners may be reluctant to post issues with warranty implications. If so, they can PM me the any details they're comfortable with sharing.

Purpose is (1) answer my FL friend's question and (2) find driving techniques for reducing the likelihood of issues with the rear end.

Ranger

bernrex

I'd think that a dead hook would be more apt to slip the clutch .... while wheel hop is more stressful on the rear shafts/tranny.

Ranger

Hey bernrex. I've seen them break on a dead hook launch with a stock clutch and an aftermarket clutch. Didn't happen on the first pass of the day either. But it always seemed that track prep was quite good.

Ranger

niphilli2

Seems to me like I remember an issue with the half shafts in early production units that was corrected, beefed up or heat treated or something. Anyone else recall this?

Ranger

From Rodney at RPM Transmissions:

"Since the majority of the croud here have moved up from C5's the replacement of output shafts is very familiar. I have a C6 Z06 differential apart right now and the LH (long) shaft is the same size as the OE shaft found in the previous C5 diffs . The RH (short) shaft has been upgraded to a two piece style like we have been doing for a while in the aftermarket world. I'm sure there will be a lot of broken shafts in the near future ***WARNED*** "

Differential output shaft replacement

Ranger

Another Yellow

Ranger this is from the thread that you quoted and my original reply.
I replied BS, not because I didn't believe FSTR-N-U but because that shouldn't have been happening without a reason. I did some checking since then and this is what I found out.

First of all, the first failure of a halfshaft occurred in a CTF (Captured-Fleet Test Car). It was fixed for customer cars with improved heat treat and longer length.

This next quote is from the same thread.

As far as the halfshaft breaking 3 times, it can be done. Side step the clutch at 7,000 rpm wide open throttle with the traction control off. As soon as the tires spin up, smoking but not moving, power shift to second and side step the clutch again. If that doesn't break it, do the same thing in third

It is appears that his car had the original halfshaft and two of the replacement parts were also original as GM might not have replaced all of the original halfshafts in their parts inventory. The problem seems to have been fixed with the most recent halfshaft that was installed. What he says about a new part is also correct as heavy duty forged design will be used sometime in April. This will be part of continued improvement that occurs regularly and there will not be a retrofit to earlier cars.

I think you can tell your Florida friend that there is no need to worry.

Frank

Yogivette

Looks like i will just have to break mine in may to make sure i get the upgraded one....

Sorry for the ignorance what does "side-stepping" the clutch mean.

Ranger

Yogivette, "Side-stepping" the clutch means

(1) with the clutch depressed, hold a particular engine rpm

(2) slide your left foot to the left and off the peddle and cause the clutch peddle to pop out by the stored hydraulic pressure.

Though difficult to believe, the acceleration times specified by the Corvette Program Office for the C5Z06 were achieved by side-stepping the clutch on launch. Here is a quote from a test regime document that was posted here in 2002:

"Subject: 0-60mph / Drag strip Test Format for 2002 Z06 Corvette

0-60 MPH & 1/4 MILE ACCELERATION

VEHICLE PREP Cold tire pressures F/R 30/30 psi. Active Handling turned off. A/C turned off. Full tank of fuel.

DRIVING TECHNIQUE First an optimum launch rpm must be established which is a function of ambient temperature, sun load, track surface, tire temperature, vehicle loading .... etc. An optimum launch will allow enough wheel spin so that when the tires "hook up" to the pavement there is not a loss in vehicle acceleration. Find your optimum launch rpm by holding the engine rpm between approximately 1500 and 3500 rpm (depending on test conditions), then side step the clutch and go to full throttle. Do not slip the clutch, side stepping the clutch allows the engine inertia to break the tires loose from the pavement. If you get excessive wheel spin, lower your launch rpm. If the vehicle acceleration "sags", increase your launch rpm. Some conditions require the driver to control wheel spin with throttle control, some do not. Speed shift all gear changes without lifting your foot off the throttle. Our Corvette drivetrain is designed for this. Data analysis subtracts 1 foot time and corrects test conditions to 60 degrees F."

At Carslile 2002, I asked Dave Hill about the "side-stepping" of the clutch on launch and he confirmed it.

Ranger

outnumbered

EMINENT 1

At what rpm before redline do you let out the clutch when you speedshift, Ranger?

Ranger

Haven't powershifted the C6Z. I do some lift on the shift but still manage to complete the shift quickly. Am trying to shift as close to the limiter as possible without kissing it. Still learning the rhythm of this motor.

Ranger

bernrex

Excellent info Ranger ! This is for the old Z .... hopefully they designed the new drivetrain to handle this shifting technique as well.

Ranger

Hey bernrex. They actually have the computer Nanny minding the launch and shifts and invoking Torque Management to protect the drive-train. Fastest 60' reported for a stock car on DRs is low 1.7x. That's more than a tenth slower than it should be. So a driver work-around technique is needed. That's what I'm focusing on if it gets warm enough to run here again.

Ranger

bernrex

With time ... you will outsmart that Nanny and get it down to 1.6's