Hello, I apologize in advance for asking a question I'm probably not supposed to ask. But I'm desperate! I've been to 2 Chevy dealerships and a Corvette Performance shop. I've asked everyone I can (including posting on different corvette forums, yes here too) and no one can diagnose what's causing an intermittent vibration on my 2004 C5 Corvette. All agree the problem exists but haven't a clue as to what it is. The Vette has 37,000 miles and 27,000 miles on it, when purchased 1 and 1/2 years ago. It starts around 60 mph, last for a second or so, goes away for a second or so and comes back and keeps repeating. Increase speed, it doesn't change in any way, doesn't get louder, stronger, make noise, continues whether turning or going straight. Everything has been checked, and nothing found broke, bent, cracked, missing, unaligned, and no one can find anything wrong. According to Auto Check car has never been wrecked. New wheels and tires, alignment(s), new brake pads and rotors, 1 half shaft replaced, 4 shocks replaced, engine runs great, transmission shifts fine (vibration is still there even after shifting into neutral and/or gun the engine). I did receive 1 reply concerning centering the torque converter or maybe something wrong with the torque tube assembly. Since I understand these are expensive repairs, and I ain't made out of money (retired), it'd be nice if I can get a definite answer as to what the problem is.
Any help would be appreciated.
Thanks

 

One overlooked point of interest is the front suspension bushings. When they deteriorate they will cause intermittent vibrations. I would look very closely there. Most times these are overlooked while chasing the usual suspects (tires, rims, rotors, brake pads, wheel hubs, etc)

 

I also wouldn't rule out wind resistance at those speeds. If something is amiss it could cause a vibration (air dam and such).

 

Moved to C5 Tech.

 

I'm actually fighting the same EXACT issue with my C5 right now, but I get the weird pulsing vibration starting at 70mph, versus 60mph. What I've done so far: alignment, Bilstein sport shocks, rims/tires (used but balanced), brake rotors/pads, front ball joints (upper and lower), and front wheel bearings. Of all those things, the front ball joints/wheel bearings seemed to make a noteworthy improvement, but I may be imagining things. I plan to do the rear ball joints/wheel bearings next. Following that, I will try new tires since my current ones are about 4 years old, and then control arm bushings. If all that doesn't fix it...I'm gonna deal with it. I've made a ton of modifications/upgrades in the last 6 months and replacing all the wear components I just listed was on my to-do list anyway. So I don't have any hard feelings about it, but it'd sure be nice if they would solve the issue!

Based on the repeatability and consistency of the vibration, I am leaning more towards a drive line vibration. I've got Hinson motor/trans mounts, DSS poly torque tube couplers, twin disk clutch, ECS trans axle brace, etc. I wouldn't be surprised if I introduced a new harmonic vibration into the drive line. I haven't checked to see if the vibration goes away in neutral and under different load conditions. If it doesn't goes away in neutral, you can weigh out any drive line components behind the flywheel/converter being the root cause.

My recommendation would be wheel bearings next...as I mentioned, I saw a noteworthy improvement after changing my front bearings. I am hoping after I do the rears, the remaining vibration will go away entirely.

Let us know if you figure it out! I'm interested in what solves it for you. I'll be sure to let you know if I get to the bottom of it as well!

 

I also have this exact issue.

At 70+, I get a vibration. It comes on softly, peaks, goes away softly, over about a second, second and a half. Wait about the same amount of time. Vibration pattern repeats. Doesn't matter what gear. Only really feel it on a very smooth road but it is very clearly there. Revving in neutral does not cause it.

I have done:
- New tires, balanced
- New wheels, balanced (different shop)
- New shocks, Viking double-adjustable, various combinations, no change
- New rotors and pads
- New big brakes (wilwood rotors, pads, calipers)

At this time I believe it is likely to be the control arm bushings. Especially the fronts.

Why? Two reasons.

One, mine are old (97k miles, 15-ish years) and are noted to be in not great shape. Especially the fronts.

Two, a guy just talked about this during his OneTake - C6Z not C5 - he replaced his bushings and the problem went away.

 

Sounds like I’ll be moving control arm bushings to the front of my list! At least that’s a cheap and relatively easy option.

 

This weekend I am going to be swapping my front OE rubber upper control arm bushings with poly units. I'll report back on the results! I am not rushing in to do the lowers at the same time in an effort to save on getting an alignment...again. If the vibration is unchanged, I'll bite the bullet and do lowers next weekend. After that, new tires...then rear wheel bearings, ball joints, tie rods, and control arm bushings...

All these nickel and dime jobs are hurting my go-fast parts budget

 

I've been fighting a similar vibration. At first, I had Hinson poly mounts for the engine and trans, I swapped the trans mount back to stock and that DRASTICALLY reduced the issue. I was clearly getting some drivetrain vibes.

Now, I still have a little bit that I'm trying to chase down. Perhaps the control arm bushings are due. I don't think I want the harshness of poly, anyone find good rubber or something replacements?

 

To report back, poly front control arm bushings (upper and lower) did the trick. No more vibration in the front end/steering wheel! Smooth as butter into the triple digits.

Im still getting a constant faint vibration from the rear end above 80 that’s different from the pulsing vibration up front. It really doesn’t bother me at all since I rarely drive that fast, but I’ll probably start collecting parts to perform the same overhaul on the rear as I did the front (wheel bearings, control arm bushings, tie rods, ball joints, etc). Eventually 4 new tires also.

All in all, I’m happy since that front end vibration is gone.