QKSLVR Z

i have a constant vibration coming from my 96 C4.. doesnt matter what gear you are in, but it vibrates at 3000 rpms.. could the u-joints need replacing? rebalance driveshaft? anyone else had/have this problem?

thanks
vinnie

radwebster

if it doesn't matter what gear its in, then it shouldn't be driveshaft or anything past transmission. i would look closer to the motor, maybe harmonic balancer? (just guessing) but the drive shaft and such are gonna be spinning different rpm's in different gears, so it shouldn't be those

AZ Z51

If it was speed I would say it was the drive shaft ,butyou sa it is RPM related.And that would be the balancer

HammerDown

I've got the same problem on my 94. Is it only at 3k, or is the vibration present beyond that point, too?
Mine starts at about 3500 rpm and is present all the way to redline.

I've changed the flywheel and clutch, had the balance checked on both, and looked at the harmonic balancer. All looked good. We think it's a bad balancer, though. The outer ring can slip and throw off the balance a bit. I'm going to try putting a mark on the outer and inner ring, drive it around for a while with a few WOT runs, then see if the marks moved. Of course if it move once and hasn't moved since, the balancer will look good but will actually be out of balance.

QKSLVR Z

it's only between 3000-3500 rpms.. if i floor it and go through all the gears, it's fine.. will a new balancer be the fix?

thanks
vinnie

comp

good plan

Frizlefrak

It's most likely your balancer. I'm in the process of replacing mine right now. I drove the car to work the other day, and on the way home, it developed a hellacious vibration. At first I thought I had something broken or loose in the driveline or suspension, but then it occured to me that it went away when I let off the throttle. Took a look under the hood, and the outer ring of the balancer was doing the macarena on the hub.

I bought a new one from Corvette Central for around $65. I just finished pulling the old one this afternoon, and the new one is going back on tomorrow.

Check your balancer, I would be willing to bet it's getting ready to disintegrate. Make sure you get a good puller, and it comes off fairly easily.

QKSLVR Z

Frizle, a new balancer for $65? is this OEM? i think i saw them in PACE parts for $380.. just want to make sure we are talking about the same thing.. got a part #? i just ordered a few things from corvette central too..

thanks
vinnie

SilverBeast

I agree on the balancer.
Here's the scoop from GM PARTS DIRECT:
GM
Part # Category Description Pack Qty Unit Price Quantity Ext.
Price YOU
SAVE Core Charge S&H Approx TOTAL
*12551486
Engine Crankshaft and Camshaft Balancer
BALANCER
1
$305.32
$305.32
$230.33
$0.00
$61.06
$366.38
(this started out on one line)
THis is for VIN 5 (LT1)

QKSLVR Z

i have a LT4.. i guess they are different..

thanks
vinnie

SilverBeast

This is for LT4:
GM
Part # Category Description Pack Qty Unit Price Quantity Ext.
Price YOU
SAVE Core Charge S&H Approx TOTAL
*10128489
Engine Crankshaft and Camshaft Balancer
BALANCER
1
$300.15
$300.15
$226.43
$0.00
$60.03
$360.18

Subtotal:
$360.18



* indicates special order item, which is a special order non-returnable part.

BTW - their quoted shipping prices are typically WAY higher than they actually charge.

QKSLVR Z

thanks! did frizle order something different then for $65?

vinnie

SilverBeast

Yeah, probably what my son calls a "bobo product." (Generic) It may work but I tend to stay with the General on stuff in driveline.

HammerDown

So unless you hold the engine rpms right at 3000-3500 rpm, the vibration is not noticeable? Hmmm...

Has it vibrated the whole time you've owned the car? If so, the balancer may not be installed on the crank correctly. In my case, the vibration started a couple of years after I bought the car, so that means something moved on it's own or "went bad".

Frizlefrak

It came from Corvette Central, part # 303224, and the price was actually $69.95. It shows years 72-91 on the invoice. Looks like a Chinese knockoff of the original part.

As for the original part, Midway Chevrolet wanted $129 and had to order it. It remains to be seen if there is a quality difference, but even the general is outsourcing stuff all over the globe. Had I ordered an OEM replacement, I might have wound up with the same part I have sitting in my garage.

Besides, Corvette Central stands behind their stuff.

Edit....I'm looking through the CC catalogue, and they don't show a balancer for the 92-96. Ecklers does in the GM restoration section and it is $499.99 m Good God....I didn't realize they were so high OEM. If your balancer is bad, I hope you can find an aftermarket replacement.

QKSLVR Z

i might also want to add that my LT4 has over 100k miles.. yea, pretty much around the 3000-3500 rpm range, i get a vibration.. anything after that or under that, it's gone..

thanks
vinnie