[Joshinator99]

Originally Posted by Redlinez

How much less does the GM Perf ZL1 shaft weigh than a SS? How much are they?

I'd imagine that it weighs more...

[TJay74]

Originally Posted by oldman

Agree that if the shaft breaks, I like carbon fiber. I have never heard of a ZL1 shaft breaking... so for a true street car that needs a shaft, I went with the GM performance shaft, basically a ZL1 shaft that bolts into the SS. As stated above I would not consider an aluminum shaft because if it breaks (and they do), you could be in REAL trouble.

Don't know what to say about the response or drivability? Rotational momentum is related to the square of radii, and this is 1 and 3/4 inch... not much. compared to say a 29" diameter tire. About 55X more important.'

From GForces's site: "The 3.5” or 4" aluminum driveshaft is rated to 900hp and speeds up to around 160 mph with no issues or vibrations. As they say “smooth as glass” at 160 mph."

I'm looking at this or even more HP and even though I don't drive 160 MPH, my car is capable of such. Once again I'll point to that I know of no ZL1 driveshaft issues (not including convertible).

Which OEM ZL1 did you end up going with, is it a bolt in item?

[oldman]

Originally Posted by TJay74

Which OEM ZL1 did you end up going with, is it a bolt in item?

https://sdparts.com/i-24104126-chevr...ft-system.html

https://www.chevrolet.com/performanc...maro/drag-race


You can get it for about $1000 shipped. It is back-order so expect to wait.

[cmitchell17]

Does anyone think the stock 2 piece driveshaft along with the excessive slope in the rubber carrier fake bearing thing is the reason for the cheap sounding clunks and sorry NVH qualities the camaro has? (especially when shifting between drive and reverse) Or is it just the excessive backlash GM like to build into the ring and pinion gear? I can't believe no one else notices it and its quite embarrassing to have almost brand new car clunk and clang every time you shift to reverse and clunk every time you let on and off the gas. My assumption is the gear in the SS with the cooler option is probably set up with more backlash due to operating temps that could be encountered on the track than a standard differential.

Sorry to derail the thread but I would consider a aftermarket driveshaft a lot more if it helps this horrible NVH problem the camaro has.

[asrautox]

Originally Posted by cmitchell17

Does anyone think the stock 2 piece driveshaft along with the excessive slope in the rubber carrier fake bearing thing is the reason for the cheap sounding clunks and sorry NVH qualities the camaro has? (especially when shifting between drive and reverse) Or is it just the excessive backlash GM like to build into the ring and pinion gear? I can't believe no one else notices it and its quite embarrassing to have almost brand new car clunk and clang every time you shift to reverse and clunk every time you let on and off the gas. My assumption is the gear in the SS with the cooler option is probably set up with more backlash due to operating temps that could be encountered on the track than a standard differential.

Sorry to derail the thread but I would consider a aftermarket driveshaft a lot more if it helps this horrible NVH problem the camaro has.

Us 6 speed cars have zero clunks, I'm betting it's your auto..

[cmitchell17]

I'm almost positive its the excessive backlash in the ring and pinion. If the car is parked on a hill facing down it completely eliminates it since the wheels are trying to push the rest of the driveline forward so it takes up the slack. Then you can put it in drive or reverse and it feels like a normal car.

[6spdhyperblue]

No clunking here. Do you have a tune? Did it do it stock?. There’s a setting in the transmission to minimize clunking.

My 6spd doesn’t do that tho

Maybe ur lucky and ur universal is shot?

[asrautox]

Originally Posted by cmitchell17

I'm almost positive its the excessive backlash in the ring and pinion. If the car is parked on a hill facing down it completely eliminates it since the wheels are trying to push the rest of the driveline forward so it takes up the slack. Then you can put it in drive or reverse and it feels like a normal car.

Next time you park the car on a normal grade try putting it in neutral, engage the parking brake, then let go of the brake. Put it in park and go about your business. Next time you start the car and put it in D or R, I'll bet it doesn't clunk..

[oldman]

The stock shaft is really a well made item and the SS manual is the same shaft as the Zl1 convertible manual. FYI. My stock shaft is 14 lbs including the center bearing and support but not the 12 bolts and 2 rubber donuts (don't know what happened to them). It has been posted the whole thing is 22 lbs which is believable....

[cmitchell17]

Originally Posted by asrautox

Next time you park the car on a normal grade try putting it in neutral, engage the parking brake, then let go of the brake. Put it in park and go about your business. Next time you start the car and put it in D or R, I'll bet it doesn't clunk..

You are exactly right, you preload the driveshaft and take up the slack. I drove an ATS loaner with the 2.0T and the issue seemed somewhat better but still present, which is especially ridiculous on a Cadillac. My logic tells me its got to be extra backlash added for high temp operation, the 14bolt FF axel in my Duramax was the same way but worse, you could almost literally count seconds before hitting the gas and feeling the bank clunk when all the slack was finally taken up. It also makes a very audible noise through the whole car, which is surprising that GM did so much to make so much stuff quite but ignored this.

[cmitchell17]

Originally Posted by 6spdhyperblue

No clunking here. Do you have a tune? Did it do it stock?. There’s a setting in the transmission to minimize clunking.

My 6spd doesn’t do that tho

Maybe ur lucky and ur universal is shot?

Yes I am, and I've tried it with the torque shaping parameter engaged and I couldn't tell that it made any difference. I think a lot of parameters are there and available to change in HP Tuners, but whether or not they actually work and were tested is a different story.


I think they could have eliminated this through software, maybe they couldn't because of patent infringement or something?

[asrautox]

Originally Posted by cmitchell17

You are exactly right, you preload the driveshaft and take up the slack. I drove an ATS loaner with the 2.0T and the issue seemed somewhat better but still present, which is especially ridiculous on a Cadillac. My logic tells me its got to be extra backlash added for high temp operation, the 14bolt FF axel in my Duramax was the same way but worse, you could almost literally count seconds before hitting the gas and feeling the bank clunk when all the slack was finally taken up. It also makes a very audible noise through the whole car, which is surprising that GM did so much to make so much stuff quite but ignored this.

Except what you’re actually doing is decoupling your transmission from any driveline loads. It removes the clunk because your transmission doesn’t have to break the parking load to shift into gear. The clunk is the auto, not the driveshaft/diff.


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[cmitchell17]

Originally Posted by asrautox

Except what you’re actually doing is decoupling your transmission from any driveline loads. It removes the clunk because your transmission doesn’t have to break the parking load to shift into gear. The clunk is the auto, not the driveshaft/diff.


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Where in the transmission is there this much slack/backlash? What about the slop in the rubber carrier bushing in the center support moving up and down?

You can make the same clunk happen when coasting and letting DFCO come on then press the gas and its loud enough its easily heard and felt driving. It drives me insane haha

[oldman]

the center support is really flimsy. If I had any issues I would look into pouring liquid urethane into it.