Crazy Cowboy

OK, so when I bought my latest C6Z I noticed on the highway when I had the windows up (the exhaust is RIDICULOUSLY LOUD so it pretty much hides any other noise) that I had a minor whine when going 75mph+. Nothing major. Almost like a throwout bearing on the clutch in some of my other past non-Vette vehicles....

Just took a 400 mile road trip and got stuck in about 2-3 hours of really heavy highway rain. By the time I got back from the trip it wasn't raining but I noticed the whine is now louder and quite noticable starting at around 15-20mph and gets louder with speed.

I was thinking maybe a universal joint on the driveshaft but then isn't the driveshaft really only spinning as fast as the flywheel / motor since the transmission is in the back? There's no change in whine regardless of clutch in or out. It does quiet down a bit when coasting (not under accel or decel load) so I'm GUESSING it could be my rear end gears or maybe a half-shaft going out?

Any ideas or recommendations are very much appreciated. I will be draining the fluid in the trans and rear tomorrow to look for any metal shavings and checking the shafts and anything else for visible clues of wear or loose parts externally. Still drives smooth and no issues other than the whine. Just the noise level has increased from the trip to the point of concern now.

Ketchum

U/joints don't whine. Throwout bearings don't whine. If its really a whine I bet your on the right track. Trans or diff. I think your guess maybe correct from your description.

Crazy Cowboy

Not the news I was hoping for.... I'm thinking my fluid change tomorrow should give me an idea which one it's coming from IF it's actually wearing and not a bearing making noise. Anyone recommend a good place to buy or have the Z differential built / rebuilt? Central FL area would be ideal.

Z06Brucey

Begin a GM Vette tech I usually dont see the new C6Z's with rear end noise. However I have replaced 1-2 shift synchro's for whine noise, but more for "parking lot" speeds.

speedraider

I go to Matt @ FSP in Bradenton. Its a 2 hour drive but he knows his stuff and doesn't rape you like everyone around here. He did the blower install and tune on my car, good guy to deal with.

Matt @ FSP

Hey bud.. You can bring it by our shop one day and we'll take a look at it, see if we can discern where it is coming from on the lift, loaded, etc.

I have had some issues with brand new 2011+ differentials whining from the factory actually, but that is right out of the box...

Crazy Cowboy

Thanks Matt. I talked to Jeff and I'm going to bring it over by there after the weekend since he's right around the corner vs 2 1/2 hours away. I really appreciate your help on the phone. Hopefully I can get out there to your shop sometime soon

speedraider

I'm going over tuesday, follow me. it will only take us an hour and a half....

truckplay

swerve from side to side and listen (wheel bearings - tires)
accel / decel - (diff)
clutch in / out (throw-out bearing)
constant at engine speed (alternator, pulleys/ bearings)
a/c on / off (ac compressor - idler pulley)

good luck

speedraider

My rear wheel bearing went bad and the noise started at 30 mph and going straight as an arrow. Go Gators...

Ketchum

Usually a big difference from a whine to roars. I've never heard a wheel bearing 'whine' or throwout bearings.

SUB VETTE

I had a front wheel bearing go out - no whine, just vibration which felt like it was the driveline.

Crazy Cowboy

Totally speed dependent. Clutch in / out doesn't matter. Swerving left & right doesn't matter. NO vibration or pulsing at any speed. Minor reduction in noise level when coasting with no accel / decel load. Maybe a tiny bit louder under harder load (hard to tell with exhaust that rattles your teeth loose). Starts around 25mph and gets higher pitched and louder with speed. My guesses are either a bearing in the transmission on a shaft or (BOY IT WOULD BE NICE) a half-shaft CV joint going bad. Sounds like it's coming from the shifter. Matt says it could possibly be a torque tube issue. That would also be great because it's not a fortune to fix unless it's vibrated other tolerances and gears out of whack..... Guess I'll find out next week.... No nice weather cruising in the Z this weekend I guess

Anyone know of someone with a dyno in the central FL area that might be available to put the car up tomorrow and diagnose it while things are turning at speed enough to hear it underneath the car???? I'm planning on NLP but they can't get me in til Tues. If I could figure out what it is tomorrow I could fix it or at least start a tear-down over the weekend depending what it is. A half-shaft would be way too easy! I doubt it's that because there's no vibration. The whine did start after about 2.5hrs of very heavy rain on the highway - which I've never driven in before. Wondering if a CV boot is broken it could be a dry bearing starting to fail. Hmmmmm

Mongose

2006 Z06. 21,000 mi. Recently acquired from family member.
I'm experiencing 1st, 2nd, and 3rd low speed rattling noise from my transmission. After accelerating and RPMs increase the noise seems to go away. Dealer says it's normal on some cars. I suspect otherwise. I noticed you mentioned the synchro gears. Could this be my problem or is it something else. The dealers don't seem to want to do anything or can't do anything. Car runs and shifts fine. Annoying to have to listen to the noise. Thinking I might have to get an after market trans. Thoughts?

23/C8Z

no one mentioned it so i will since i had this happen to me when i purchased my '08..

It could also be the rear bearing in the torque tube.. mine was rattling, whining.. At idle it was an intermittent light rattle coming from under the car (some days no rattle at all) which would straighten out above idle but then start to whine..

i removed the torque tube and replaced it with new one from gm. i sold the old one before i had the chance to open and inspect but from another forum i found a woman who went through the same problem and she chose to let her mechanic fix the old tube...

the rear portion of the torque tube in her vette somehow was retaining or absorbing moisture... the rear bearing was corroded, badly.. and the car maybe had 50k on it.. so, when you mentioned that after a hard rain you noticed a difference i figured i would just bring that up... best of luck, now matter what it is it can be fixed!

found some pics of hers..

Bigspoker

I recently purchased a 2011 GS manual with under 24k miles. There is a low whine that’s increasing in pitch as you accelerate in 1st, 2nd & 3rd but disappears completely in 4th gear. Thoughts? Costs?