Well folks, searched the site and couldn't find this but, it may just be normal, idk. I have a 1998, black/black coupe with manual trans. I have just added a Hurricane CAI and Corsa Sport with X. Funny but, when we changed out the exhaust from stock, a noticeable drone in my driveline became apparent. It shows up under load only, in any gear, including reverse. In other words, whenever I am giving it gas and it's under load. Low speed, high speed, it doesn't seem to matter. Can't tell whether it's in the front (clutch) or in the rear (trans). It sounds more rear to me when I'm in the driver's seat. But, sometimes it sounds like it may be coming from the front and the torque tube is transferring it to the rear. Again, if I let up on the throttle it disappears, give it gas and it comes back. Any thoughts would be greatly appreciated. Thanks...

Dunno how many miles on your Corvette or if the fluid has been changed or if you have experienced leaks from the seals. I'd drain and fill the rear with the new GM fluid. Best of luck

Sorry, meant to mention all of that. Pretty new to posting on the forum. It has 106,000 on the odo and yes we went through and changed all of the fluids just after I bought it with 103,000. We did find, after the noise came on (thinking as you are), that the fluid levels were both over filled. We attributed that to the probability that the rear end was probably lifted when they did it. We proceded to drain and change them. The car has absolutely no squeaks or leaks, including the shocks, and all of the cases. Actually, it is in such condition that we show it. Took a second place, C5 Stock, at the first show entered on Father's Day this year. I know that has no bearing on the mechanics of it but, should indicate that it was well maintained. Have all the original service records and there's nothing there to indicate a previous problem which might have led to this. Thanks for answering though...I guess we'll just go with my mechanic's suggestion of running until it either gets worse and we can isolate, or to complete fail (guess which one I'm hoping occurs first...) Thanks again...Tom (seeyabye)

Well if you put the exhaust on and your getting a drone? I might suggest its the exhaust itself. They can drone..(hard to tell exactly what the word drone describes)

Since you're attending corvette shows? Why not speak with other club members who live in your area and ask to go for a ride in their vehicles with similiar brand exhausts..

You can then determine if its the aftermarket exhaust or the installation..(something might be moving and or vibrating or hitting causing the sound...or it might be just the exhaust itself...? Could be one of the connectors or hangers as well.

I would be shocked if it were a fluid level since you state the issue cropped up after the aftermarket exhaust installation

That would be my suggestion...

Noise is hard to describe on the net..

There is a website...very technical in nature that might be of greater assistance. www.corvettemechanics.com

HTH and welcome to this great site..

My first c5 a4 1999 ...I put corsa indys on and it sounded great...but there was if I remember correctly a drone compared to the stock exhaust...

My c5 z06 with cam/headers/gears had a drone after the installation...

My stock 2008 C6 Z51 with NPP M6 has a drone on the highway if I set the M2W switch to keep the exhaust flaps from the factory open all the time....If I leave it in factory spec's on the highway...no drone..

I love the aftermarket exhausts but both installation and the realization drones can occur must be accepted..(again...hard to describe or understand the term drone on the net) Could be your x pipe too? Maybe rubbing or leaking under revving motor...as motor rocks a bit..it moves pipes a little which is normal but then possible contact not visable on a lift and the engine not rocking a little as is normal?

Maybe rev the motor to 4K rpms with the clutch in and in neutral...? I bet you'd hear the drone.. then...and then you have a clue to maybe check and recheck clearances and exhaust hangers? or x pipe contact to chassis? under rpms where the engine will as normal rock a bit which would shift the pipes to rub or possible exhaust leak?

Just guessing...best to meet up with some other corvette owners local with the same exhaust as yours to decide the next path of action..


JB

After you changed the diff fluid did you remember to add the friction modifier?

JB...thank you for the response. I understand your statement about the exhaust drone (which is why I went with Corsa, for those long road trips) and seeing as how they were just put on it might lead to your diagnosis. So, to clear things up a bit, by drone I mean it sounds like a whirring sound somewhere between a low and high pitch and comes on whenever under throttle, no matter the revs. Thanks for the link to corvettemechanics.com, I'll give them a holler also.

Smoken...yep, and the diff change was an effort to locate/resolve the problem. Alex, the fellow I deal with, owns Rocky Mountain Corvette and is deep into track racing and this even has him stumped for an immediate cause/solution. Which is why we're letting it go for the moment. It's very driveable, just the sound is annoying when I don't have the stereo on and want to listen to the Corsas sounding off. I'm sure we'll find it, and when we do, I'll post what we eventually found. Thanks everyone for the input.

If anybody else has some thoughts, by all means let me know. Always open and willing to learn. Especially since this is my first Corvette. To paraphrase an old, dear departed friend, "tis a privilige to own a Corvette"...Tom

The drive shaft has rubber donuts that can go? I remember I had them replaced with BMW parts that were the same without having to buy the entire driveshaft...

I had spoken about it over at www.corvettemechanics.com

Not sure if it would cause droning though...

Its been too long for me to remember..

The drive shaft has rubber donuts that can go? I remember I had them replaced with BMW parts that were the same without having to buy the entire driveshaft...

I had spoken about it over at www.corvettemechanics.com

Not sure if it would cause droning though...

Its been too long for me to remember..I really doubt it but thought I'd just throw it out there...

Does it make the noise rolling down a hill with the clutch engaged and the car in neutral..?

I would think it would be quite a coincidence for the diff or something else to suddenly start making noise right after the exhaust installation. I would be looking to see if the exhaust is contacting the car somewhere underneath or maybe where the tips exit. Or, as JB said, it might just be a charateristic of this exhaust. I installed a Borla system on my C4 that had a nearly unbearable drone right around 60 mph.