348 vibration when turning

Differential chatter??

 

Sounds like a classic symptom of a bad CV joint. If it was my car, I would probably check the torque on the wheel lug bolts first. Then I would check for any signs of a tear in one of the four CV joint rubber boots that might be letting grease out and dirt and water in. Then I would check the torque on the bolts that hold the joints onto the drive flanges. If nothing turns up on any of these checks, you may need to repack the CV joints. Or you may need to drain the transmission and check for signs of metal in the gear oil.

It also wouldn't hurt to check your tires for signs of "cupping" in the tread.

 

I had a similar thing a few weeks ago. It turned out to be a small bolt stuck in te edge of my tire. Naturaly I first asumed it would be a wheel bearing, steering rack or CV. But sometimes you win. Mike.

 

Beside lugnuts and cv joints, I'd suggest simply pulling and releasing the emergency brake during a parking lot speed turn (to see if the problem goes away or worsens). As they wear out/age, our 348 parking brake shoes can grab in turns.

And that's a pretty cheap, quick test, too.

The noise/vibrations from a grabbing parking brake shoe are pretty well in the same location as your cv joints, making it difficult to feel or hear which is which, but pulling on the ebrake at slow speeds will tell you if it's an old brake shoe or not.

Another cheap thing to check would be tire inflation (might as well eyeball your tread for an unusual wear pattern, too).

Also, my old Corvette would start vibrating at anything over 20mph whenever it was time for new rubber (it also helps to replace all four tires at once so that you don't experience the difference between broken-in tires versus new tires with the 300 mile new-tire chemical compound still on). There would still be tread left at that point, but not enough to justify vibrating around town.

Try all of the cheap, quick tests first before you start throwing money at the problem, though.

 

Have you changed gear oil to one with no LSD additive recently?

 

I think NoDoubt is on to something. You may have your parking break still engaged. Makes sure it isn't still set. Pull the parking break handle all the way up then press the button. As you continue to hold the button down lower the handle then release the button.

 

Did the vibration start after you had the wheels off and back on or since the service was done. I would suggest rechecking your wheel torque and centering. Your car does'nt have stock wheels and one may not be fully seated or loose. It my be just that simple.

 

Never heard of that. Hill Type-2 spacers bolt to the hub, then the wheel bolts to the spacer. A type-1 spacer just uses longer bolts but is perfectly smooth. Any pics of yours?

On OEM hubs there are little nipples that are used for wheel hanging (quite poorly, I might add). Maybe that's what you're referring to?

-d